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Evidence for bisphenol A-induced female infertility: a review (2007–2016)

      We summarized the scientific literature published from 2007 to 2016 on the potential effects of bisphenol A (BPA) on female fertility. We focused on overall fertility outcomes (e.g., ability to become pregnant, number of offspring), organs that are important for female reproduction (i.e., oviduct, uterus, ovary, hypothalamus, and pituitary), and reproductive-related processes (i.e., estrous cyclicity, implantation, and hormonal secretion). The reviewed literature indicates that BPA may be associated with infertility in women. Potential explanations for this association can be generated from experimental studies. Specifically, BPA may alter overall female reproductive capacity by affecting the morphology and function of the oviduct, uterus, ovary, and hypothalamus-pituitary-ovarian axis in animal models. In addition, BPA may disrupt estrous cyclicity and implantation. Nevertheless, further studies are needed to better understand the exact mechanisms of action and to detect potential reproductive toxicity at earlier stages.

      Key Words

      Female infertility is generally defined as the inability to get pregnant naturally and to deliver a live healthy newborn. According to the Centers for Disease Control and Prevention (CDC; http://www.cdc.gov/nchs/nsfg/key_statistics/i.htm#infertility), between 2011 and 2013, 6.1% of married women were considered to be infertile in the United States alone. The percentage of infertile women can reach 30% worldwide (
      • Inhorn M.C.
      • Patrizio P.
      Infertility around the globe: new thinking on gender, reproductive technologies and global movements in the 21st century.
      ). Infertility in women can be the result of various factors, including physical problems, endocrine problems, lifestyle habits, and environmental factors. Environmental factors, such as exposure to chemicals with endocrine disrupting properties, can mimic or block the endocrine activity of endogenous hormones and thus adversely affect reproduction.
      One of the most extensively studied endocrine disrupting chemicals is bisphenol A (BPA). Bisphenol A is incorporated in many daily used products; it is used by the manufacturers of polycarbonate plastics and epoxy resins. Despite the relatively short half-life of BPA (6–24 hours) (
      • Volkel W.
      • Colnot T.
      • Csanady G.A.
      • Filser J.G.
      • Dekant W.
      Metabolism and kinetics of bisphenol a in humans at low doses following oral administration.
      ), it was measured in various reproductive tissues (
      • Vandenberg L.N.
      • Hauser R.
      • Marcus M.
      • Olea N.
      • Welshons W.V.
      Human exposure to bisphenol A (BPA).
      ), including ovarian follicular fluid, placenta, breast milk, and colostrum. Findings from previous publications suggest that BPA is a reproductive toxicant (
      • Peretz J.
      • Vrooman L.
      • Ricke W.A.
      • Hunt P.A.
      • Ehrlich S.
      • Hauser R.
      • et al.
      Bisphenol a and reproductive health: update of experimental and human evidence, 2007–2013.
      ,
      • Vandenberg L.N.
      • Ehrlich S.
      • Belcher S.M.
      • Ben-Jonathan N.
      • Dolinoy D.C.
      • Hugo E.R.
      • et al.
      Low dose effects of bisphenol A.
      ,
      • Maffini M.V.
      • Rubin B.S.
      • Sonnenschein C.
      • Soto A.M.
      Endocrine disruptors and reproductive health: the case of bisphenol-A.
      ).
      The current review focuses on the scientific evidence for BPA-induced fertility problems in females. We summarized the main findings of epidemiological and experimental studies that examined the potential effects of BPA on female fertility and that were published between 2007 and 2016. We included the morphological and mechanistic findings reported in the reviewed articles. We focused on the reported outcomes of BPA exposure on overall: [1] fertility, [2] reproductive-related processes including the ovarian cycle, and [3] reproductive tissues.

      Materials and methods

      PubMed (http://www.ncbi.nlm.nih.gov/pubmed) searches for the years 2007–2016 were conducted using the following key words: BPA, bisphenol A, fertility, female, reproduction, ovary, pregnancy, oviduct, ovulation, fertilization, uterus, implantation, hypothalamus, and pituitary. We focused on articles published in 2007–2016 to expand on previous review reports on the same topic (
      • Peretz J.
      • Vrooman L.
      • Ricke W.A.
      • Hunt P.A.
      • Ehrlich S.
      • Hauser R.
      • et al.
      Bisphenol a and reproductive health: update of experimental and human evidence, 2007–2013.
      ,
      • Vandenberg L.N.
      • Ehrlich S.
      • Belcher S.M.
      • Ben-Jonathan N.
      • Dolinoy D.C.
      • Hugo E.R.
      • et al.
      Low dose effects of bisphenol A.
      ,
      • Fowler P.A.
      • Bellingham M.
      • Sinclair K.D.
      • Evans N.P.
      • Pocar P.
      • Fischer B.
      • et al.
      Impact of endocrine-disrupting compounds (EDCs) on female reproductive health.
      ,
      • Caserta D.
      • Di Segni N.
      • Mallozzi M.
      • Giovanale V.
      • Mantovani A.
      • Marci R.
      • et al.
      Bisphenol A and the female reproductive tract: an overview of recent laboratory evidence and epidemiological studies.
      ,
      • Aghajanova L.
      • Giudice L.C.
      Effect of bisphenol A on human endometrial stromal fibroblasts in vitro.
      ,
      • Machtinger R.
      • Orvieto R.
      Bisphenol A, oocyte maturation, implantation, and IVF outcome: review of animal and human data.
      ,
      • Gore A.C.
      • Chappell V.A.
      • Fenton S.E.
      • Flaws J.A.
      • Nadal A.
      • Prins G.S.
      • et al.
      EDC-2: The Endocrine Society's second scientific statement on endocrine-disrupting chemicals.
      ). In addition, references included in other review articles were examined for relevant information. We included articles that dealt with fertility/infertility outcomes related to overall fertility, implantation, uterine morphology and function, estrous cyclicity, hypothalamus-pituitary, hormone levels (luteinizing hormone [LH], follicular stimulating hormone [FSH], and prolactin [PRL]), oviduct, and ovary. We excluded articles about topics that were out of the scope of this review or ones that will be reviewed by other investigators in this special issue (e.g., sexual maturation/behavior, oocyte quality and maturation, ovarian steroidogenesis, pregnancy, miscarriage, endometriosis, polycystic ovarian syndrome [PCOS], and uterine fibroids/leiomyoma).
      The BPA studies have used various study designs and included a wide range of doses. Based on the definitions in other studies, we considered a “low dose” of BPA as follows: a dose below the lowest observable adverse effect level of 50 mg/kg/d in animal models (
      • Peretz J.
      • Vrooman L.
      • Ricke W.A.
      • Hunt P.A.
      • Ehrlich S.
      • Hauser R.
      • et al.
      Bisphenol a and reproductive health: update of experimental and human evidence, 2007–2013.
      ,
      • Vandenberg L.N.
      • Ehrlich S.
      • Belcher S.M.
      • Ben-Jonathan N.
      • Dolinoy D.C.
      • Hugo E.R.
      • et al.
      Low dose effects of bisphenol A.
      ,
      • Richter C.A.
      • Birnbaum L.S.
      • Farabollini F.
      • Newbold R.R.
      • Rubin B.S.
      • Talsness C.E.
      • et al.
      In vivo effects of bisphenol A in laboratory rodent studies.
      ,
      • Vom Saal F.S.
      • Akingbemi B.T.
      • Belcher S.M.
      • Birnbaum L.S.
      • Crain D.A.
      • Eriksen M.
      • et al.
      Chapel Hill bisphenol A expert panel consensus statement: integration of mechanisms, effects in animals and potential to impact human health at current levels of exposure.
      ), 17.2 mg/L for aquatic animals (
      • Vandenberg L.N.
      • Ehrlich S.
      • Belcher S.M.
      • Ben-Jonathan N.
      • Dolinoy D.C.
      • Hugo E.R.
      • et al.
      Low dose effects of bisphenol A.
      ,
      • Crain D.A.
      • Eriksen M.
      • Iguchi T.
      • Jobling S.
      • Laufer H.
      • LeBlanc G.A.
      • et al.
      An ecological assessment of bisphenol-A: evidence from comparative biology.
      ), 1 × 10−7 M for cell culture experiments (
      • Vandenberg L.N.
      • Ehrlich S.
      • Belcher S.M.
      • Ben-Jonathan N.
      • Dolinoy D.C.
      • Hugo E.R.
      • et al.
      Low dose effects of bisphenol A.
      ,
      • Wetherill Y.B.
      • Akingbemi B.T.
      • Kanno J.
      • McLachlan J.A.
      • Nadal A.
      • Sonnenschein C.
      • et al.
      In vitro molecular mechanisms of bisphenol A action.
      ), and a dose in the range of typical (not occupational) human exposures for epidemiological studies (
      • Vandenberg L.N.
      • Ehrlich S.
      • Belcher S.M.
      • Ben-Jonathan N.
      • Dolinoy D.C.
      • Hugo E.R.
      • et al.
      Low dose effects of bisphenol A.
      ,
      • Vandenberg L.N.
      • Colborn T.
      • Hayes T.B.
      • Heindel J.J.
      • Jacobs Jr., D.R.
      • Lee D.H.
      • et al.
      Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses.
      ). Most studies described in this review used doses that are within the category of low dose. Throughout the text of this review, we indicated if the doses were considered low or high based on these categories. In the Tables, the specific doses that were used in each study are described in detail. Last, similar to Peretz et al. (
      • Peretz J.
      • Vrooman L.
      • Ricke W.A.
      • Hunt P.A.
      • Ehrlich S.
      • Hauser R.
      • et al.
      Bisphenol a and reproductive health: update of experimental and human evidence, 2007–2013.
      ), we defined exposure time during pregnancy as in utero; exposure after birth that ended before weaning as neonatal; and exposure any time after weaning as postnatal or adult exposure.

      Results and discussion

       Overall Fertility

      In recent years, several research groups have examined the effects of BPA on overall fertility. Epidemiological studies examined whether BPA levels are higher in infertile women than in fertile women (Table 1). Findings from these studies (
      • Caserta D.
      • Bordi G.
      • Ciardo F.
      • Marci R.
      • La Rocca C.
      • Tait S.
      • et al.
      The influence of endocrine disruptors in a selected population of infertile women.
      ,
      • La Rocca C.
      • Tait S.
      • Guerranti C.
      • Busani L.
      • Ciardo F.
      • Bergamasco B.
      • et al.
      Exposure to endocrine disrupters and nuclear receptor gene expression in infertile and fertile women from different Italian areas.
      ) indicate that infertile women have higher serum BPA levels compared with fertile women. Furthermore, studies (
      • Bloom M.S.
      • Kim D.
      • Vom Saal F.S.
      • Taylor J.A.
      • Cheng G.
      • Lamb J.D.
      • et al.
      Bisphenol A exposure reduces the estradiol response to gonadotropin stimulation during in vitro fertilization.
      ,
      • Ehrlich S.
      • Williams P.L.
      • Missmer S.A.
      • Flaws J.A.
      • Ye X.
      • Calafat A.M.
      • et al.
      Urinary bisphenol A concentrations and early reproductive health outcomes among women undergoing IVF.
      ,
      • Fujimoto V.Y.
      • Kim D.
      • vom Saal F.S.
      • Lamb J.D.
      • Taylor J.A.
      • Bloom M.S.
      Serum unconjugated bisphenol A concentrations in women may adversely influence oocyte quality during in vitro fertilization.
      ,
      • Mok-Lin E.
      • Ehrlich S.
      • Williams P.L.
      • Petrozza J.
      • Wright D.L.
      • Calafat A.M.
      • et al.
      Urinary bisphenol A concentrations and ovarian response among women undergoing IVF.
      ,
      • Bloom M.S.
      • Vom Saal F.S.
      • Kim D.
      • Taylor J.A.
      • Lamb J.D.
      • Fujimoto V.Y.
      Serum unconjugated bisphenol A concentrations in men may influence embryo quality indicators during in vitro fertilization.
      ) conducted in women undergoing IVF treatments show that BPA levels (total or unconjugated BPA) were inversely associated with peak E2 levels, number of oocytes retrieved, oocyte maturation, fertilization rates, and embryo quality. Thus, increased levels of BPA may decrease the success rate of IVF treatments. Nevertheless, these studies did not take into account potential modifying factors such as co-exposure to other chemicals and the location of sample collection as pointed out by Teeguarden et al. (
      • Teeguarden J.G.
      • Waechter Jr., J.M.
      • Clewell 3rd, H.J.
      • Covington T.R.
      • Barton H.A.
      Evaluation of oral and intravenous route pharmacokinetics, plasma protein binding, and uterine tissue dose metrics of bisphenol A: a physiologically based pharmacokinetic approach.
      ,
      • Teeguarden J.G.
      • Hanson-Drury S.
      A systematic review of Bisphenol A “low dose” studies in the context of human exposure: a case for establishing standards for reporting “low-dose” effects of chemicals.
      ). Thus, additional studies are needed to fully understand the associations between BPA exposure and fertility outcomes in women.
      Table 1BPA and fertility (epidemiological studies).
      Study designStudy populationSample sizeTime of BPA measurementBPA concentrationOutcomeReference no.
      Cross-sectionalWomen undergoing IVF44Day of oocyte retrievalMedian unconjugated serum BPA 2.53 ng/mL (range, 0.3–67.36 ng/mL)BPA inversely associated with peak estradiol; no association with number of oocytes retrieved
      • Bloom M.S.
      • Kim D.
      • Vom Saal F.S.
      • Taylor J.A.
      • Cheng G.
      • Lamb J.D.
      • et al.
      Bisphenol A exposure reduces the estradiol response to gonadotropin stimulation during in vitro fertilization.
      Matched cohortWomen discontinuing contraception210On the day of expected

      menstruation
      Urine (total BPA), mean (95% confidence interval): pregnant: 0.63 ng/mL (0.54–0.73); nonpregnant: 0.68 ng/mL (0.53–0.87)No association with impaired fecundity or time to pregnancy
      • Buck Louis G.M.
      • Sundaram R.
      • Sweeney A.M.
      • Schisterman E.F.
      • Maisog J.
      • Kannan K.
      Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) Study.
      Cross-sectionalFertile and infertile Italian women12 fertile

      35 infertile
      EnrollmentNot indicated; limit of detection 0.5 ng/mL (serum samples)Higher percentage of infertile women with detectable serum BPA levels
      • Caserta D.
      • Bordi G.
      • Ciardo F.
      • Marci R.
      • La Rocca C.
      • Tait S.
      • et al.
      The influence of endocrine disruptors in a selected population of infertile women.
      ProspectiveWomen undergoing IVF239 (63 no soy food intake); 347 cyclesBetween days 3 and 9 of gonadotropin phase and on day of oocyte retrievalUrine (total BPA); Range, <0.4–16.6 μg/L; median, 1.3 μg/L (interquartile range, 0.9–1.9 μg/L)Soy food consumption modifies the correlation between BPA and infertility treatment outcomes
      • Chavarro J.E.
      • Minguez-Alarcon L.
      • Chiu Y.H.
      • Gaskins A.J.
      • Souter I.
      • Williams P.L.
      • et al.
      Soy intake modifies the relation between urinary bisphenol A concentrations and pregnancy outcomes among women undergoing assisted reproduction.
      ProspectiveWomen undergoing IVF174 (237 cycles)Day of oocyte retrievalUrinary (total BPA) geometric mean 1.50 (SD 2.22) μg/LHigher BPA levels associated with lower serum peak estradiol, oocyte yield, MII oocyte count, and number of normally fertilizing oocytes
      • Ehrlich S.
      • Williams P.L.
      • Missmer S.A.
      • Flaws J.A.
      • Ye X.
      • Calafat A.M.
      • et al.
      Urinary bisphenol A concentrations and early reproductive health outcomes among women undergoing IVF.
      ProspectiveWomen undergoing ICSI and IVF58Day of oocyte retrievalMedian unconjugated serum BPA 2.53 ng/mL (range, 0.0–67.4 ng/mL)Inverse associations between BPA and oocyte maturation (Asian women) and normal fertilization (all women)
      • Fujimoto V.Y.
      • Kim D.
      • vom Saal F.S.
      • Lamb J.D.
      • Taylor J.A.
      • Bloom M.S.
      Serum unconjugated bisphenol A concentrations in women may adversely influence oocyte quality during in vitro fertilization.
      Pregnancy-based retrospectiveWomen in 1st trimester1,742Spot urine during the 1st trimester visitUrinary (total BPA) geometric mean 0.78 (0.73–0.82) ng/mLNo association with diminished fecundity
      • Velez M.P.
      • Arbuckle T.E.
      • Fraser W.D.
      Female exposure to phenols and phthalates and time to pregnancy: the Maternal-Infant Research on Environmental Chemicals (MIREC) study.
      ProspectiveWomen undergoing IVF35 of 58Day of oocyte retrievalMedian unconjugated serum BPA 2.4 μg/L serum (range, 0.0–67.4)Up-regulation of TSP50 with increased BPA levels due to a loss of methylation
      • Hanna C.W.
      • Bloom M.S.
      • Robinson W.P.
      • Kim D.
      • Parsons P.J.
      • vom Saal F.S.
      • et al.
      DNA methylation changes in whole blood is associated with exposure to the environmental contaminants, mercury, lead, cadmium and bisphenol A, in women undergoing ovarian stimulation for IVF.
      ProspectiveFertile women that discontinued contraception221Pooled urine throughout menstrual cyclesUrinary (total BPA) median 2.7 ng/mL (interquartile range 1.8, 4.3), not adjustedBPA associated with shorter luteal phase; null associations with follicular-phase length, time to pregnancy, and early pregnancy loss
      • Jukic A.M.
      • Calafat A.M.
      • McConnaughey D.R.
      • Longnecker M.P.
      • Hoppin J.A.
      • Weinberg C.R.
      • et al.
      Urinary concentrations of phthalate metabolites and bisphenol A and associations with follicular-phase length, luteal-phase length, fecundability, and early pregnancy loss.
      Cross-sectionalWomen who volunteered110 infertile, 43 fertileWhole blood sample prior to any treatmentMean (total BPA, serum) (ng/mL): fertile 4.8 infertile 10.6BPA levels higher among infertile women (odds ratio 8.3) in metropolitan area
      • La Rocca C.
      • Tait S.
      • Guerranti C.
      • Busani L.
      • Ciardo F.
      • Bergamasco B.
      • et al.
      Exposure to endocrine disrupters and nuclear receptor gene expression in infertile and fertile women from different Italian areas.
      ProspectiveWomen undergoing IVF256 (375 cycles)Between days 3 and 9 of gonadotropin phase; and on day of oocyte retrievalUrinary (total BPA) geometric mean 1.87 μg/LNo associations with oocyte yield, endometrial thickness, embryo quality, fertilization rates, implantation, clinical pregnancy and live birth rates
      • Minguez-Alarcon L.
      • Gaskins A.J.
      • Chiu Y.H.
      • Williams P.L.
      • Ehrlich S.
      • Chavarro J.E.
      • et al.
      Urinary bisphenol A concentrations and association with in vitro fertilization outcomes among women from a fertility clinic.
      ProspectiveWomen undergoing IVF84 (112 cycles)Day of oocyte retrievalUrinary (total BPA); Range, <0.4–25.5 μg/L; urinary geometric mean 2.52 μg/L (SD 3.2)BPA levels inversely associated with the number of oocytes retrieved and peak serum estradiol levels
      • Mok-Lin E.
      • Ehrlich S.
      • Williams P.L.
      • Petrozza J.
      • Wright D.L.
      • Calafat A.M.
      • et al.
      Urinary bisphenol A concentrations and ovarian response among women undergoing IVF.
      ProspectiveWomen undergoing IVF36Day of oocyte retrievalMedian unconjugated serum BPA 3.3 ng/mL (range, 0.0–67.4 ng/mL)No association with embryo quality
      • Bloom M.S.
      • Vom Saal F.S.
      • Kim D.
      • Taylor J.A.
      • Lamb J.D.
      • Fujimoto V.Y.
      Serum unconjugated bisphenol A concentrations in men may influence embryo quality indicators during in vitro fertilization.
      Note: BPA = bisphenol A; ICSI = intracytoplasmic sperm injection.
      Limited information is available on the potential molecular targets of BPA in infertile women. Hanna et al. (
      • Hanna C.W.
      • Bloom M.S.
      • Robinson W.P.
      • Kim D.
      • Parsons P.J.
      • vom Saal F.S.
      • et al.
      DNA methylation changes in whole blood is associated with exposure to the environmental contaminants, mercury, lead, cadmium and bisphenol A, in women undergoing ovarian stimulation for IVF.
      ) reported an association between higher serum levels of unconjugated BPA and decreased methylation within the TSP50 gene promoter in whole blood samples of women undergoing IVF treatments. However, the researchers did not provide any mechanistic explanations of these findings other than to indicate that TSP50 may be an oncogene based on previous research by other groups (
      • Shan J.
      • Yuan L.
      • Xiao Q.
      • Chiorazzi N.
      • Budman D.
      • Teichberg S.
      • et al.
      TSP50, a possible protease in human testes, is activated in breast cancer epithelial cells.
      ,
      • Yuan L.
      • Shan J.
      • de Risi D.
      • Broome J.
      • Lovecchio J.
      • Gal D.
      • et al.
      Isolation of a novel gene, TSP50, by a hypomethylated DNA fragment in human breast cancer.
      ). Interesting findings reported by Chavarro et al. (
      • Chavarro J.E.
      • Minguez-Alarcon L.
      • Chiu Y.H.
      • Gaskins A.J.
      • Souter I.
      • Williams P.L.
      • et al.
      Soy intake modifies the relation between urinary bisphenol A concentrations and pregnancy outcomes among women undergoing assisted reproduction.
      ) suggest a potential modifying effect of soy food consumption on the inverse correlations between urinary total BPA concentrations and fertility treatment outcomes. Overall, these studies are suggestive for potential associations between BPA and infertility. However, additional studies are needed to determine a possible cause and effect relationship and the mechanism of action of BPA-mediated effects on fertility in healthy women.
      Not all epidemiological studies found an association between BPA exposure and fertility outcomes. Null associations were reported between urinary total BPA concentrations and impaired fecundity or time to pregnancy in generally healthy women (
      • Buck Louis G.M.
      • Sundaram R.
      • Sweeney A.M.
      • Schisterman E.F.
      • Maisog J.
      • Kannan K.
      Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) Study.
      ,
      • Velez M.P.
      • Arbuckle T.E.
      • Fraser W.D.
      Female exposure to phenols and phthalates and time to pregnancy: the Maternal-Infant Research on Environmental Chemicals (MIREC) study.
      ,
      • Jukic A.M.
      • Calafat A.M.
      • McConnaughey D.R.
      • Longnecker M.P.
      • Hoppin J.A.
      • Weinberg C.R.
      • et al.
      Urinary concentrations of phthalate metabolites and bisphenol A and associations with follicular-phase length, luteal-phase length, fecundability, and early pregnancy loss.
      ). In another study (
      • Minguez-Alarcon L.
      • Gaskins A.J.
      • Chiu Y.H.
      • Williams P.L.
      • Ehrlich S.
      • Chavarro J.E.
      • et al.
      Urinary bisphenol A concentrations and association with in vitro fertilization outcomes among women from a fertility clinic.
      ), null associations between urinary total BPA concentrations and number of oocytes retrieved, embryo quality, and fertilization rates were reported in women undergoing IVF treatments. The differences in the results may be explained by differences in sample characteristics (i.e., generally healthy women without any reported infertility issues vs. women undergoing IVF treatments) and by differences in sample size.
      Studies using animal models provide further insights on the effects of BPA exposure on female fertility (Table 2). In mice, Berger et al. (
      • Berger R.G.
      • Hancock T.
      • deCatanzaro D.
      Influence of oral and subcutaneous bisphenol-A on intrauterine implantation of fertilized ova in inseminated female mice.
      ) reported that low dose BPA exposure of pregnant dams during the preimplantation period significantly reduced the number of litters and litter size compared with controls. Furthermore, in utero low dose BPA exposure after implantation affected the fertility of the females in the subsequent generations (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ,
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      ). Cabaton et al. (
      • Cabaton N.J.
      • Wadia P.R.
      • Rubin B.S.
      • Zalko D.
      • Schaeberle C.M.
      • Askenase M.H.
      • et al.
      Perinatal exposure to environmentally relevant levels of bisphenol A decreases fertility and fecundity in CD-1 mice.
      ) performed a forced breeding study and found that low dose BPA-exposed females had fewer pregnancies and overall reduced cumulative number of pups compared with controls. Moore-Ambriz et al. (
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      ) examined the effects of BPA exposure in young adult mice on fertilization capacity later in adult life. The fertilization rate of BPA exposed females was reduced compared with controls. Furthermore, impaired fertility was also reported in a study that examined the effects of in utero low dose BPA exposure in three subsequent generations of mice (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ,
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      ). Specifically, F1 females that were gestationally exposed to BPA had reduced fertility, reduced litter size (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ), and reduced ability to maintain pregnancy to term (i.e., reduced gestational index) compared with controls (
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      ). Furthermore, F2 females had a reduced gestational index compared with controls (
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      ). In addition, F3 females exhibited reduced fertility and decreased ability to become pregnant compared with controls, indicating a potential transgenerational effect of BPA on female reproduction (
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      ). In chickens, in ovo high dose BPA exposure reduced hatchability (
      • Yigit F.
      • Daglioglu S.
      Histological changes in the uterus of the hens after embryonic exposure to bisphenol A and diethylstilbestrol.
      ), whereas in fish, low dose BPA exposure increased the observed hatching rate (
      • Qiu W.
      • Zhao Y.
      • Yang M.
      • Farajzadeh M.
      • Pan C.
      • Wayne N.L.
      Actions of bisphenol A and bisphenol S on the reproductive neuroendocrine system during early development in zebrafish.
      ).
      Table 2BPA and fertility (experimental studies).
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      MouseCF-1Subcutaneous injectionGD1-40–10.125 mg/dAfter birthBPA10.125 reduced percent of females giving birth; BPA3.4 and 10.125 reduced number of pups born
      • Berger R.G.
      • Hancock T.
      • deCatanzaro D.
      Influence of oral and subcutaneous bisphenol-A on intrauterine implantation of fertilized ova in inseminated female mice.
      MouseCD-1Alzet osmotic pumpGD8– PND1625 ng, 250 ng, 25 μg/kg/dF1: from 8 wk until 32 wk (forced breeding)BPA 25 ng females had fewer pregnancies and lower cumulative number of pups per dam that got worse with age
      • Cabaton N.J.
      • Wadia P.R.
      • Rubin B.S.
      • Zalko D.
      • Schaeberle C.M.
      • Askenase M.H.
      • et al.
      Perinatal exposure to environmentally relevant levels of bisphenol A decreases fertility and fecundity in CD-1 mice.
      MouseC57BL/6NHsd, Hsd:ICR (CD-1 Swiss)Extruded pellet dietsPrior to breeding-PND210.03, 0.3, 30 ppmAfter birthNo effect on fertility of C57BL6; decreased fertility of CD-1 (BPA0.03 and 0.3)
      • Kendziorski J.A.
      • Kendig E.L.
      • Gear R.B.
      • Belcher S.M.
      Strain specific induction of pyometra and differences in immune responsiveness in mice exposed to 17alpha-ethinyl estradiol or the endocrine disrupting chemical bisphenol A.
      MouseC57BL/6JDietaryGD6–PND210.33, 3.3, 33 ppmAfter birthNo effect on number of births or litter size
      • Kobayashi K.
      • Ohtani K.
      • Kubota H.
      • Miyagawa M.
      Dietary exposure to low doses of bisphenol A: effects on reproduction and development in two generations of C57BL/6J mice.
      RatSprague-DawleyDietaryGD6–PND210.33, 3.3, 33 ppmAfter birthNo effect on number of births or litter size
      • Kobayashi K.
      • Kubota H.
      • Ohtani K.
      • Hojo R.
      • Miyagawa M.
      Lack of effects for dietary exposure of bisphenol A during in utero and lactational periods on reproductive development in rat offspring.
      FishPimephales promelasAquarium water164 d exposure1, 16, 64, 160, 640 μg/LOn exposure days 85–105, 135–155No effect on fecundity
      • Mihaich E.
      • Rhodes J.
      • Wolf J.
      • van der Hoeven N.
      • Dietrich D.
      • Hall A.T.
      • et al.
      Adult fathead minnow, Pimephales promelas, partial life-cycle reproductive and gonadal histopathology study with bisphenol A.
      MouseC57BL/6J (39 d)Oral12–15 d (first 3 reproductive cycles)50 μg/kg/dAge 51–54 dReduced fertilization (in vitro fertilization or mating); did not alter zygotic stages
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      FishTransgenic zebrafishAquariumEmbryonically0.1, 1, 10, 100, 1,000 μg/L48, 55 h after fertilizationBPA1 and 10 increased hatching rate
      • Qiu W.
      • Zhao Y.
      • Yang M.
      • Farajzadeh M.
      • Pan C.
      • Wayne N.L.
      Actions of bisphenol A and bisphenol S on the reproductive neuroendocrine system during early development in zebrafish.
      RatLong EvansOral gavage + lactationGD7–PND182, 20, 200 μg/kg/dAfter birth and over 4 moNo effect on litter size
      • Ryan B.C.
      • Hotchkiss A.K.
      • Crofton K.M.
      • Gray Jr., L.E.
      In utero and lactational exposure to bisphenol A, in contrast to ethinyl estradiol, does not alter sexually dimorphic behavior, puberty, fertility, and anatomy of female LE rats.
      RatWistarOral, drinking waterGD9–birth0.5, 50 μg/kg/dAfter birthNo effect on litter size or number of births
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      RatWistarDrinking water + lactationGD9–PND210.5, 50 μg/kg/dAfter birthNo effect on litter size
      • Vigezzi L.
      • Bosquiazzo V.L.
      • Kass L.
      • Ramos J.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to bisphenol A alters the differentiation and functional response of the adult rat uterus to estrogen treatment.
      MouseFVBOralGD11–birth0.5, 20, 50 μg/kg/dF1: 3, 6, 9 moBPA0.5 reduced fertility with age, increased % dead pups with time (3–9 mo); BPA50 reduced litter size (6 mo)
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      MouseCD-1Oral gavageF0: GD1–PND2012, 25, 50 mg/kg/dAfter birthNo effect on litter size
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      ChickenWhite LeghornIn ovo injectionIncubation d 467, 134 μg/g eggHatchingDecreased hatchability (BPA 67, 134)
      • Yigit F.
      • Daglioglu S.
      Histological changes in the uterus of the hens after embryonic exposure to bisphenol A and diethylstilbestrol.
      MouseCD-1OralGD12.5–PND18.50.2, 0.04, 0.08 mg/kgPND1No effect on litter size
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      MouseFVBOral of pregnant dams (F0)GD11–birth0.5, 20, 50 μg/kg/dF1, F2, F3: 3, 6, 9 moBPA50 reduced gestational index (F1, F2); BPA0.5 reduced fertility index (F3); Reduced % of dead pups (F3, BPA20, 50); decreased ability to maintain pregnancy with age
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      Note: BPA = bisphenol A.
      In contrast, some experimental studies (
      • Kendziorski J.A.
      • Kendig E.L.
      • Gear R.B.
      • Belcher S.M.
      Strain specific induction of pyometra and differences in immune responsiveness in mice exposed to 17alpha-ethinyl estradiol or the endocrine disrupting chemical bisphenol A.
      ,
      • Kobayashi K.
      • Ohtani K.
      • Kubota H.
      • Miyagawa M.
      Dietary exposure to low doses of bisphenol A: effects on reproduction and development in two generations of C57BL/6J mice.
      ,
      • Kobayashi K.
      • Kubota H.
      • Ohtani K.
      • Hojo R.
      • Miyagawa M.
      Lack of effects for dietary exposure of bisphenol A during in utero and lactational periods on reproductive development in rat offspring.
      ,
      • Mihaich E.
      • Rhodes J.
      • Wolf J.
      • van der Hoeven N.
      • Dietrich D.
      • Hall A.T.
      • et al.
      Adult fathead minnow, Pimephales promelas, partial life-cycle reproductive and gonadal histopathology study with bisphenol A.
      ,
      • Ryan B.C.
      • Hotchkiss A.K.
      • Crofton K.M.
      • Gray Jr., L.E.
      In utero and lactational exposure to bisphenol A, in contrast to ethinyl estradiol, does not alter sexually dimorphic behavior, puberty, fertility, and anatomy of female LE rats.
      ,
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      ,
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      ,
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      ) reported that BPA exposure does not affect fertility outcomes. Specifically, a few studies (
      • Kendziorski J.A.
      • Kendig E.L.
      • Gear R.B.
      • Belcher S.M.
      Strain specific induction of pyometra and differences in immune responsiveness in mice exposed to 17alpha-ethinyl estradiol or the endocrine disrupting chemical bisphenol A.
      ,
      • Kobayashi K.
      • Ohtani K.
      • Kubota H.
      • Miyagawa M.
      Dietary exposure to low doses of bisphenol A: effects on reproduction and development in two generations of C57BL/6J mice.
      ,
      • Kobayashi K.
      • Kubota H.
      • Ohtani K.
      • Hojo R.
      • Miyagawa M.
      Lack of effects for dietary exposure of bisphenol A during in utero and lactational periods on reproductive development in rat offspring.
      ,
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      ) indicate that gestational low dose BPA exposure did not alter number of litters or litter size (
      • Kendziorski J.A.
      • Kendig E.L.
      • Gear R.B.
      • Belcher S.M.
      Strain specific induction of pyometra and differences in immune responsiveness in mice exposed to 17alpha-ethinyl estradiol or the endocrine disrupting chemical bisphenol A.
      ,
      • Kobayashi K.
      • Ohtani K.
      • Kubota H.
      • Miyagawa M.
      Dietary exposure to low doses of bisphenol A: effects on reproduction and development in two generations of C57BL/6J mice.
      ,
      • Kobayashi K.
      • Kubota H.
      • Ohtani K.
      • Hojo R.
      • Miyagawa M.
      Lack of effects for dietary exposure of bisphenol A during in utero and lactational periods on reproductive development in rat offspring.
      ,
      • Mihaich E.
      • Rhodes J.
      • Wolf J.
      • van der Hoeven N.
      • Dietrich D.
      • Hall A.T.
      • et al.
      Adult fathead minnow, Pimephales promelas, partial life-cycle reproductive and gonadal histopathology study with bisphenol A.
      ,
      • Ryan B.C.
      • Hotchkiss A.K.
      • Crofton K.M.
      • Gray Jr., L.E.
      In utero and lactational exposure to bisphenol A, in contrast to ethinyl estradiol, does not alter sexually dimorphic behavior, puberty, fertility, and anatomy of female LE rats.
      ,
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      ,
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      ,
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      ) in mice, rats, and fish. Xi et al. (
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      ) also indicate that gestational BPA exposure at a dose of 50 mg/kg/d (i.e., lowest observable adverse effect level) did not alter litter size in mice. Similarly, Moore-Ambriz et al. (
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      ) reported that low dose BPA exposure did not affect the size of preovulatory follicles, the number of shed oocytes, and zygotes in adult mice that were exposed to BPA at a younger age. One of the reasons for differences between the reported results may be the age of the animals. Studies that examined reproductive capacity in older animals were more likely to observe a difference between the BPA-treated females and controls.
      In summary, several studies indicate that BPA levels may be higher among infertile women than fertile women and that BPA exposure may reduce fertility in animal models. However, further studies are needed to link findings from epidemiological studies and experimental studies.
      To provide information about the potential mechanisms by which BPA impairs fertility, we focus on reproductive organs that are targeted by BPA in a manner that could reduce fertility. Specifically, the later sections focus on BPA-induced abnormalities in reproductive organs that stem from changes in morphology, function, gene expression, and levels of proteins or hormones related to reproduction. We review the recent studies on the effects of BPA on the oviduct, uterus and implantation, estrous cyclicity, ovary, and hypothalamic-pituitary-ovarian axis.

       Oviduct

      After ovulation, the oocyte travels from the ovary through the oviduct to allow fertilization. Upon successful fertilization, the conceptus will continue to travel through the oviduct until it is settles in the uterus. Thus, a normal functioning oviduct is required for fertility. The available recent evidence on the effects of BPA exposure on the oviduct is extremely limited and is based only on experimental studies in mice (Table 3). Specifically, in utero low dose BPA exposure resulted in the appearance of progressive proliferative lesions in the oviduct and remnants of the Wolffian duct during adult life (
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Long-term adverse effects of neonatal exposure to bisphenol A on the murine female reproductive tract.
      ,
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.
      ). Furthermore, studies (
      • Pan X.
      • Wang X.
      • Sun Y.
      • Dou Z.
      • Li Z.
      Inhibitory effects of preimplantation exposure to bisphenol-A on blastocyst development and implantation.
      ,
      • Xiao S.
      • Diao H.
      • Smith M.A.
      • Song X.
      • Ye X.
      Preimplantation exposure to bisphenol A (BPA) affects embryo transport, preimplantation embryo development, and uterine receptivity in mice.
      ) indicate that in utero high dose BPA exposure delayed development and transport of the conceptus compared with controls. Taken together, the current data indicate that gestational BPA exposure may affect both oviduct morphology and function; however, further studies are needed to confirm whether this is the case in women and to examine potential molecular mechanisms of BPA action on the oviduct.
      Table 3BPA and oviduct (experimental studies).
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      MouseCD-1Subcutaneous injectionGD 1510, 100, 1,000 μg/kg/d18 moIncreased progressive proliferative lesions; remnants of Wolffian ducts
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Long-term adverse effects of neonatal exposure to bisphenol A on the murine female reproductive tract.
      MouseCD-1Subcutaneous injectionGD 9–160.1, 1, 10, 100, 1,000 μg/kg/d18 moIncreased progressive proliferative lesions
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.
      MouseNot indicatedOral gavageGD 0.5–3.5200, 400, 600, 800 mg/kg/dGD4BPA 400–800 delayed transfer of embryos from fallopian tubes to uterus (GD4)
      • Pan X.
      • Wang X.
      • Sun Y.
      • Dou Z.
      • Li Z.
      Inhibitory effects of preimplantation exposure to bisphenol-A on blastocyst development and implantation.
      MouseC57BL6Subcutaneous injectionGD 0.5–3.50.025, 0.5, 10, 40, 100 mg/kg/dGD3.5BPA100 retention of embryos and delayed embryo development
      • Xiao S.
      • Diao H.
      • Smith M.A.
      • Song X.
      • Ye X.
      Preimplantation exposure to bisphenol A (BPA) affects embryo transport, preimplantation embryo development, and uterine receptivity in mice.
      Note: BPA = bisphenol A.

       Uterus

       Implantation

      Implantation is required for the establishment of pregnancy. During this stage, the blastocyst attaches to the uterine wall. Thus, exposures that interfere with implantation have the potential to impact fertility. The scientific evidence for a possible link between BPA exposure and impairments in implantation is based on one epidemiological study (Table 4) and several experimental studies (Table 5). Specifically, higher urinary total BPA levels were associated with increased implantation failure defined by a serum β-hCG (<6 IU/L) conducted 17 days after egg retrieval in women undergoing IVF treatments (
      • Ehrlich S.
      • Williams P.L.
      • Missmer S.A.
      • Flaws J.A.
      • Berry K.F.
      • Calafat A.M.
      • et al.
      Urinary bisphenol A concentrations and implantation failure among women undergoing in vitro fertilization.
      ).
      Table 4BPA and implantation (epidemiological study).
      Study designStudy populationSample sizeTime of BPA measurementBPA concentrationOutcomeReference no.
      ProspectiveWomen undergoing IVF137 (180 IVF cycles)Day of oocyte retrievalUrinary (total BPA) geometric mean 1.53 (SD 2.22) μg/LHigher BPA levels associated with increased implantation failure
      • Ehrlich S.
      • Williams P.L.
      • Missmer S.A.
      • Flaws J.A.
      • Berry K.F.
      • Calafat A.M.
      • et al.
      Urinary bisphenol A concentrations and implantation failure among women undergoing in vitro fertilization.
      Note: BPA = bisphenol A.
      Table 5BPA and implantation (experimental studies).
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      MouseCF-1Subcutaneous injectionGD 1–40–10.125 mg/dGD 6BPA10.125 decreased number of implantation sites
      • Berger R.G.
      • Hancock T.
      • deCatanzaro D.
      Influence of oral and subcutaneous bisphenol-A on intrauterine implantation of fertilized ova in inseminated female mice.
      MouseCF-1Subcutaneous injectionGD 0, 1, 20–10.125 mg/dGD 6BPA10.125 and 6.75 decreased implantation sites
      • Berger R.G.
      • Shaw J.
      • deCatanzaro D.
      Impact of acute bisphenol-A exposure upon intrauterine implantation of fertilized ova and urinary levels of progesterone and 17beta-estradiol.
      MouseCF-1Subcutaneous injectionGD 1–40–10.125 mg/dGD 6BPA6.75 and 10.125 decreased number of implantation sites
      • Berger R.G.
      • Shaw J.
      • deCatanzaro D.
      Impact of acute bisphenol-A exposure upon intrauterine implantation of fertilized ova and urinary levels of progesterone and 17beta-estradiol.
      MouseCF-1Subcutaneous injectionGD 1–43.375, 6.75, 10.125 mg/dGD 6BPA6.75 and 10.125 decreased number of implantation sites
      • Berger R.G.
      • Foster W.G.
      • deCatanzaro D.
      Bisphenol-A exposure during the period of blastocyst implantation alters uterine morphology and perturbs measures of estrogen and progesterone receptor expression in mice.
      MouseCF-1Subcutaneous injectionGD 1–43, 4, 5 mg/dGD 6No difference in number of implantation sites
      • Borman E.D.
      • Foster W.G.
      • Greenacre M.K.
      • Muir C.C.
      • deCatanzaro D.
      Stress lowers the threshold dose at which bisphenol A disrupts blastocyst implantation, in conjunction with decreased uterine closure and e-cadherin.
      MouseCF-1Subcutaneous injectionGD 1–32, 4 mg/d (61, 122 mg/kg/d)GD 6No difference in number of implantation sites
      • Crawford B.R.
      • Decatanzaro D.
      Disruption of blastocyst implantation by triclosan in mice: impacts of repeated and acute doses and combination with bisphenol-A.
      MouseCD-13 times a day feedingPND 22–GD 960, 600 μg/kg/dThrough GD 9Impaired implantation and impaired PGR-HAND2 pathway
      • Li Q.
      • Davila J.
      • Kannan A.
      • Flaws J.A.
      • Bagchi M.K.
      • Bagchi I.C.
      Chronic exposure to Bisphenol A affects uterine function during early pregnancy in mice.
      MouseNot indicatedOral gavageGD 0.5–3.5200, 400, 600, 800 mg/kg/dGD 4.5BPA 400–800 delayed transfer of embryos from fallopian tubes to uterus and decreased number of implantation sites
      • Pan X.
      • Wang X.
      • Sun Y.
      • Dou Z.
      • Li Z.
      Inhibitory effects of preimplantation exposure to bisphenol-A on blastocyst development and implantation.
      RatWistarSubcutaneous injectionPND 1, 3, 5, 70.05, 20 mg/kg/dGD 5, GD 18Reduced implantation sites
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Lower M.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A alters rat uterine implantation-associated gene expression and reduces the number of implantation sites.
      MouseC57BL6Subcutaneous injectionGD 0.5–3.50.025, 0.5, 10, 40, 100 mg/kg/dGD 4.5No implantation sites (BPA100); delayed implantation (BPA40)
      • Xiao S.
      • Diao H.
      • Smith M.A.
      • Song X.
      • Ye X.
      Preimplantation exposure to bisphenol A (BPA) affects embryo transport, preimplantation embryo development, and uterine receptivity in mice.
      MouseC57BL6Subcutaneous injectionGD 0.5–3.5100 mg/kg/dGD 4.5No implantation sites when untreated embryos transferred to pseudopregnant females pretreated with BPA100
      • Xiao S.
      • Diao H.
      • Smith M.A.
      • Song X.
      • Ye X.
      Preimplantation exposure to bisphenol A (BPA) affects embryo transport, preimplantation embryo development, and uterine receptivity in mice.
      Note: BPA = bisphenol A.
      Experimental studies (
      • Berger R.G.
      • Hancock T.
      • deCatanzaro D.
      Influence of oral and subcutaneous bisphenol-A on intrauterine implantation of fertilized ova in inseminated female mice.
      ,
      • Pan X.
      • Wang X.
      • Sun Y.
      • Dou Z.
      • Li Z.
      Inhibitory effects of preimplantation exposure to bisphenol-A on blastocyst development and implantation.
      ,
      • Berger R.G.
      • Shaw J.
      • deCatanzaro D.
      Impact of acute bisphenol-A exposure upon intrauterine implantation of fertilized ova and urinary levels of progesterone and 17beta-estradiol.
      ,
      • Berger R.G.
      • Foster W.G.
      • deCatanzaro D.
      Bisphenol-A exposure during the period of blastocyst implantation alters uterine morphology and perturbs measures of estrogen and progesterone receptor expression in mice.
      ,
      • Li Q.
      • Davila J.
      • Kannan A.
      • Flaws J.A.
      • Bagchi M.K.
      • Bagchi I.C.
      Chronic exposure to Bisphenol A affects uterine function during early pregnancy in mice.
      ,
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Lower M.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A alters rat uterine implantation-associated gene expression and reduces the number of implantation sites.
      ) examining the effects of BPA exposure at early gestational stages report a reduced number or complete ablation of implantation sites (
      • Xiao S.
      • Diao H.
      • Smith M.A.
      • Song X.
      • Ye X.
      Preimplantation exposure to bisphenol A (BPA) affects embryo transport, preimplantation embryo development, and uterine receptivity in mice.
      ) in mice and rats when compared with controls. These studies include both low (
      • Berger R.G.
      • Hancock T.
      • deCatanzaro D.
      Influence of oral and subcutaneous bisphenol-A on intrauterine implantation of fertilized ova in inseminated female mice.
      ,
      • Berger R.G.
      • Shaw J.
      • deCatanzaro D.
      Impact of acute bisphenol-A exposure upon intrauterine implantation of fertilized ova and urinary levels of progesterone and 17beta-estradiol.
      ,
      • Berger R.G.
      • Foster W.G.
      • deCatanzaro D.
      Bisphenol-A exposure during the period of blastocyst implantation alters uterine morphology and perturbs measures of estrogen and progesterone receptor expression in mice.
      ,
      • Li Q.
      • Davila J.
      • Kannan A.
      • Flaws J.A.
      • Bagchi M.K.
      • Bagchi I.C.
      Chronic exposure to Bisphenol A affects uterine function during early pregnancy in mice.
      ,
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Lower M.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A alters rat uterine implantation-associated gene expression and reduces the number of implantation sites.
      ) and high (
      • Pan X.
      • Wang X.
      • Sun Y.
      • Dou Z.
      • Li Z.
      Inhibitory effects of preimplantation exposure to bisphenol-A on blastocyst development and implantation.
      ) BPA doses. Furthermore, a recent study by Li et al. (
      • Li Q.
      • Davila J.
      • Kannan A.
      • Flaws J.A.
      • Bagchi M.K.
      • Bagchi I.C.
      Chronic exposure to Bisphenol A affects uterine function during early pregnancy in mice.
      ) demonstrated that low dose BPA exposure reduced uterine levels of leukemia inhibitory factor (Lif), P receptor (PR; Pgr), heart and neural crest derivatives expressed transcript 2 (Hand2), and homeobox A10 (Hoxa10) compared with controls. These observed BPA-mediated effects can impair fertility because these factors are part of the P-mediated signaling pathway and are important in uterine receptivity and implantation.
      Although most studies indicate that BPA alters implantation, two experimental studies report no effect of low dose (
      • Borman E.D.
      • Foster W.G.
      • Greenacre M.K.
      • Muir C.C.
      • deCatanzaro D.
      Stress lowers the threshold dose at which bisphenol A disrupts blastocyst implantation, in conjunction with decreased uterine closure and e-cadherin.
      ) or a relatively high dose (122 mg/kg/d) (
      • Crawford B.R.
      • Decatanzaro D.
      Disruption of blastocyst implantation by triclosan in mice: impacts of repeated and acute doses and combination with bisphenol-A.
      ) of BPA on the number of implantation sites. The reasons for these discordant results are unclear, but it may be that the effects of BPA on implantation are ablated at high doses.

       Uterine morphology and function

      For proper blastocyst invasion, implantation, and successful pregnancy, the uterine endometrium transforms and reorganizes under the influence of estrogen (E) and P. Thus, exposures that interfere with uterine function have the potential to adversely impact fertility. Based on our search criteria, we did not locate epidemiological studies that focus on BPA exposures and associations with uterine outcomes. However, several in vivo and in vitro experimental studies have examined the effects of BPA exposure on the uterus or uterine cells (Table 6, Table 7).
      Table 6BPA and uterus (morphology and function) experimental studies (in vivo).
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      Non-human primateAfrican green monkeyAlzet minipumpAdult50 μg/kg/dEnd of 28 d of treatmentBPA increased levels of glandular and stromal PR; BPA + E2 benzoate decreased PR expression; BPA may antagonize estradiol effects on PR expression
      • Aldad T.S.
      • Rahmani N.
      • Leranth C.
      • Taylor H.S.
      Bisphenol-A exposure alters endometrial progesterone receptor expression in the nonhuman primate.
      RatSprague-DawleySubcutaneous injectionPND 17–1910, 100, 500 mg/kg/dPND20BPA500 changed levels of contraction-associated proteins and decreased uterine contractility
      • An B.S.
      • Ahn H.J.
      • Kang H.S.
      • Jung E.M.
      • Yang H.
      • Hong E.J.
      • et al.
      Effects of estrogen and estrogenic compounds, 4-tert-octylphenol, and bisphenol A on the uterine contraction and contraction-associated proteins in rats.
      RatSprague-DawleyCultured uterine tissuePND 2010−5 M24, 48 hDecreased uterine contractility
      • An B.S.
      • Ahn H.J.
      • Kang H.S.
      • Jung E.M.
      • Yang H.
      • Hong E.J.
      • et al.
      Effects of estrogen and estrogenic compounds, 4-tert-octylphenol, and bisphenol A on the uterine contraction and contraction-associated proteins in rats.
      MouseCF-1Subcutaneous injectionGD 1–43.375, 6.75, 10.125 mg/dGD6BPA6.75 and 10.125 increased uterine luminal area and cell height
      • Berger R.G.
      • Foster W.G.
      • deCatanzaro D.
      Bisphenol-A exposure during the period of blastocyst implantation alters uterine morphology and perturbs measures of estrogen and progesterone receptor expression in mice.
      RatWistarSubcutaneous injectionPND 1, 3, 5, 70.05, 20 mg/kg/d(Ovx PND80) PND94BPA0.05 decreased endometrial proliferation, decreased levels of Vegf and Esr1 in subepithelial cells, and Esr1 in endothelial cells; BPA0.05, 20 increased expression of Ncor1 in subepithelial cells
      • Bosquiazzo V.L.
      • Varayoud J.
      • Munoz-de-Toro M.
      • Luque E.H.
      • Ramos J.G.
      Effects of neonatal exposure to bisphenol A on steroid regulation of vascular endothelial growth factor expression and endothelial cell proliferation in the adult rat uterus.
      MouseCD-1Intraperitoneal injectionGD 9–165 mg/kg2, 6 wk oldIncreased Hoxa10 mRNA and HOXA10 protein levels; hypomethylation of promoter and intron of Hoxa10
      • Bromer J.G.
      • Zhou Y.
      • Taylor M.B.
      • Doherty L.
      • Taylor H.S.
      Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response.
      Non-human primatesMacaca mulattaOralGD 50–100 or GD 100–165400 μg/kg/dGD100 or GD 165 (fetuses)Differences in levels of HOX and Wnt/Fzd family genes on GD 165
      • Calhoun K.C.
      • Padilla-Banks E.
      • Jefferson W.N.
      • Liu L.
      • Gerrish K.E.
      • Young S.L.
      • et al.
      Bisphenol A exposure alters developmental gene expression in the fetal rhesus macaque uterus.
      RatSprague-DawleyOral gavageGD 6–birth2.5, 8, 25, 80, 260, 840, 2,700, 100,000, 300,000 μg/kg/dF1 PND90No effect on Vegfa, Pgr, S100g, or C3 expression
      • Camacho L.
      • Basavarajappa M.S.
      • Chang C.W.
      • Han T.
      • Kobets T.
      • Koturbash I.
      • et al.
      Effects of oral exposure to bisphenol A on gene expression and global genomic DNA methylation in the prostate, female mammary gland, and uterus of NCTR Sprague-Dawley rats.
      MouseICRSubcutaneous injectionGD 12–16100, 200, 500, 1,000 mg/kg/dNot directly exposed F2 (8 wk)BPA100 decreased uterine weight; possible effects on Hoxa10 methylation
      • Hiyama M.
      • Choi E.K.
      • Wakitani S.
      • Tachibana T.
      • Khan H.
      • Kusakabe K.T.
      • et al.
      Bisphenol-A (BPA) affects reproductive formation across generations in mice.
      ChickenWhite LeghornIn ovo injectionIncubation d 467, 134 μg/g egg21 wk oldDecreased uterine tubular glandular density and tunica mucosa thickness (BPA134)
      • Yigit F.
      • Daglioglu S.
      Histological changes in the uterus of the hens after embryonic exposure to bisphenol A and diethylstilbestrol.
      MouseCD-1 SwissExtruded pellet diets0.03, 0.3, 30 ppmBPA0.3 increased sensitivity to develop pyometra (C57BL6)
      • Kendziorski J.A.
      • Kendig E.L.
      • Gear R.B.
      • Belcher S.M.
      Strain specific induction of pyometra and differences in immune responsiveness in mice exposed to 17alpha-ethinyl estradiol or the endocrine disrupting chemical bisphenol A.
      MouseICRInjectionAdult (OVX)10–500 mg/kg2 h after injectionBPA regulated Egr1 expression through ER-ERK1/2 pathways; BPA induced phosphorylation of AKT and ERK1/2 via non-genomic actions of ERs
      • Kim H.R.
      • Kim Y.S.
      • Yoon J.A.
      • Lyu S.W.
      • Shin H.
      • Lim H.J.
      • et al.
      Egr1 is rapidly and transiently induced by estrogen and bisphenol A via activation of nuclear estrogen receptor-dependent ERK1/2 pathway in the uterus.
      RatWistarDrinking water and lactationGD 6–PND 2110 mg/L (1.2 mg/kg/d)F1 4 moIncreased thickness of uterine epithelia and stroma
      • Mendoza-Rodriguez C.A.
      • Garcia-Guzman M.
      • Baranda-Avila N.
      • Morimoto S.
      • Perrot-Applanat M.
      • Cerbon M.
      Administration of bisphenol A to dams during perinatal period modifies molecular and morphological reproductive parameters of the offspring.
      MouseICRSubcutaneous injectionPND 80.1, 1, 10, 100 mg/kgPND 25, 30, 70Reduced uterine weight (BPA100)
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      MouseCD-1Subcutaneous injectionGD 1–510, 100, 1000 μg/kg/d18 moCystic endometrial hyperplasia (BPA100)
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Long-term adverse effects of neonatal exposure to bisphenol A on the murine female reproductive tract.
      MouseCD-1Subcutaneous injectionGD 9–160.1, 1, 10, 100, 1,000 μg/kg/d18 moAdenomatous hyperplasia (BPA1 and 100), stromal polyps (BPA100), endometrial polyps (BPA0.1, 1 and 10), squamous metaplasia (BPA1 and 10), and remnants of Wolffian duct (all except BPA100)
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.
      MouseCD-1Intraperitoneal injectionGD 9–160.5, 1.0, 5.0,

      50, 200 mg/kg
      F1 2–6 wk after birthIncreased HOXA10 in dose response fashion (BPA0.5-5)
      • Smith C.C.
      • Taylor H.S.
      Xenoestrogen exposure imprints expression of genes (Hoxa10) required for normal uterine development.
      RatWistarSubcutaneous injectionNeonatal PND 1, 3, 5, and 70.05, 20 mg/kg/dPND 8, (OVX at PND 80) PND 94PND8: downregulation of Hoxa10, Hoxa11; PND94: downregulation of Esr1, Hoxa11 (BPA0.05), and Hoxa10 (BPA 0.05, 20); impaired proliferative response to P+E (BPA0.05 and 20)
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to Bisphenol a impairs the uterine response to ovarian steroids in the adult.
      RatWistarSubcutaneous injectionNeonatal PND 1, 3, 5, and 70.05, 20 mg/kg/dF1 GD 5 or GD 18Reduced implantation sites, decreased Hoxa10, ITGB3, Pr and Esr1, increased Emx-2 (BPA20); Decreased Esr1 (BPA0.05 and 20) and PRa and PRb (BPA20)
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Lower M.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A alters rat uterine implantation-associated gene expression and reduces the number of implantation sites.
      RatWistarDrinking water + lactationGD 9–PND 210.5, 50 μg/kg/dF1 PND 90, PND 360PND 90: decreased glandular epithelium proliferation (BPA0.5 and 50) and decreased percentage of α-SMA-positive stromal cells (BPA50); PND 360: increased anomalies in uterine luminal epithelium (BPA0.5, 50) and glands (BPA50)
      • Vigezzi L.
      • Bosquiazzo V.L.
      • Kass L.
      • Ramos J.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to bisphenol A alters the differentiation and functional response of the adult rat uterus to estrogen treatment.
      Note: BPA = bisphenol A.
      Table 7BPA and uterus (morphology and function) experimental studies (in vitro).
      SourceStrainExposure routeDosesTime of observationOutcomeReference no.
      HumanEndometrial stromal fibroblastsCulture5–100 μmol/L48 hDecreased proliferation, induced IGFB1 (BPA50), decreased CYP11A, HSD17B1, HSD17B2; no effect on PRL levels
      • Aghajanova L.
      • Giudice L.C.
      Effect of bisphenol A on human endometrial stromal fibroblasts in vitro.
      HumanIshikawa cellsCulture1 μM24 hBPA or BPA + estradiol increased levels of PR; BPA + estradiol decreased PR expression compared to estradiol only; BPA may antagonize estradiol effects on PR expression
      • Aldad T.S.
      • Rahmani N.
      • Leranth C.
      • Taylor H.S.
      Bisphenol-A exposure alters endometrial progesterone receptor expression in the nonhuman primate.
      HumanEndometrial endothelial cellsCulture0.1, 50, 100 nM24 hBPA0.1-100 decreased proliferation and viability; BPA100 increased necrosis
      • Bredhult C.
      • Backlin B.M.
      • Olovsson M.
      Effects of some endocrine disruptors on the proliferation and viability of human endometrial endothelial cells in vitro.
      HumanEndometrial endothelial cellsCulture50 μM24 hDecreased cell proliferation
      • Bredhult C.
      • Sahlin L.
      • Olovsson M.
      Gene expression analysis of human endometrial endothelial cells exposed to Bisphenol A.
      HumanPrimary stromal endometrial cells (proliferative phase)Culture0.01 mM, 0.01 μM, 0.01 nM; decidualization induced by P424, 48, 72 hNo effect on proliferation; BPA (0.01 μM and 0.01 nM) increased G2/M and decreased G0/G1 fractions; BPA increased PRL (0.01 μM and 0.01 nM), LEFTY (0.01 μM), and IGFBP1 (0.01 mM, 0.01 μM and 0.01 nM)
      • Forte M.
      • Mita L.
      • Cobellis L.
      • Merafina V.
      • Specchio R.
      • Rossi S.
      • et al.
      Triclosan and bisphenol A affect decidualization of human endometrial stromal cells.
      Human5 cycling women undergoing hysterectomyCulture10 μM, 0.1 μM, 1 nM, 0.01 nM24 hNo effect on cell viability or proliferation; Increased angiogenic activity (10 μM); no difference in VEGF, ESR2, and GPR30 levels
      • Helmestam M.
      • Davey E.
      • Stavreus-Evers A.
      • Olovsson M.
      Bisphenol A affects human endometrial endothelial cell angiogenic activity in vitro.
      HumanDecidualized stromal cellsCulture1–100 pM, 1–100 nM, 1–100 μM24, 48 hNo effect on cell viability; Increased proliferation (48 h; 100 nM)
      • Mannelli C.
      • Szostek A.Z.
      • Lukasik K.
      • Carotenuto C.
      • Ietta F.
      • Romagnoli R.
      • et al.
      Bisphenol A modulates receptivity and secretory function of human decidual cells: an in vitro study.
      HumanDecidualized stromal cellsCulture1 pM, 1 nM, 1 μM24, 48 hBPA1 μM: decreased PRL; no effect on IGFBP1, increased ESR1 and ESR2 (1nM)

      BPA1 μM increased PR protein and PRA PRB mRNA; BPA1pM decreased hCG/LH-R protein and increased MIF protein secretion
      • Mannelli C.
      • Szostek A.Z.
      • Lukasik K.
      • Carotenuto C.
      • Ietta F.
      • Romagnoli R.
      • et al.
      Bisphenol A modulates receptivity and secretory function of human decidual cells: an in vitro study.
      HumanIshikawa cellsCulture1 nM, 100 nM, 10 μM, 100 μM8, 24, 48 hNo effect on cell viability; Affected multiple molecular pathways associated with cell organization and biogenesis, translation, proliferation, and intracellular transport
      • Naciff J.M.
      • Khambatta Z.S.
      • Reichling T.D.
      • Carr G.J.
      • Tiesman J.P.
      • Singleton D.W.
      • et al.
      The genomic response of Ishikawa cells to bisphenol A exposure is dose- and time-dependent.
      HumanIshikawa cellsCulture0.1 nM–25 μM, 1 μM24 hIncrease in HOXA10 in a dose response manner
      • Smith C.C.
      • Taylor H.S.
      Xenoestrogen exposure imprints expression of genes (Hoxa10) required for normal uterine development.
      Note: BPA = bisphenol A.
      In mice, in utero low dose BPA exposure increased uterine anomalies in the luminal epithelium and glands (
      • Vigezzi L.
      • Bosquiazzo V.L.
      • Kass L.
      • Ramos J.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to bisphenol A alters the differentiation and functional response of the adult rat uterus to estrogen treatment.
      ) and caused uterine hyperplasia, stromal polyps, and retention of remnants of the Wolffian duct in the adult offspring compared with controls (
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Long-term adverse effects of neonatal exposure to bisphenol A on the murine female reproductive tract.
      ,
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.
      ). Furthermore, in utero high dose BPA exposure reduced uterine weight in the second generation of pups compared with controls (
      • Hiyama M.
      • Choi E.K.
      • Wakitani S.
      • Tachibana T.
      • Khan H.
      • Kusakabe K.T.
      • et al.
      Bisphenol-A (BPA) affects reproductive formation across generations in mice.
      ). Neonatal high dose BPA exposure (single dose, 100 mg/kg) reduced uterine weight in young adult mice compared to controls (
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      ), and neonatal low dose BPA exposure decreased endometrial proliferation in adult ovariectomized rats compared with controls (
      • Bosquiazzo V.L.
      • Varayoud J.
      • Munoz-de-Toro M.
      • Luque E.H.
      • Ramos J.G.
      Effects of neonatal exposure to bisphenol A on steroid regulation of vascular endothelial growth factor expression and endothelial cell proliferation in the adult rat uterus.
      ). In young adult rats, low dose BPA exposure from gestation day 6 until weaning increased the thickness of the uterine epithelia and stroma compared with controls (
      • Mendoza-Rodriguez C.A.
      • Garcia-Guzman M.
      • Baranda-Avila N.
      • Morimoto S.
      • Perrot-Applanat M.
      • Cerbon M.
      Administration of bisphenol A to dams during perinatal period modifies molecular and morphological reproductive parameters of the offspring.
      ). In adult mice, dietary supplementation with low dose BPA resulted in clinical signs that are typical of pyometra (
      • Kendziorski J.A.
      • Kendig E.L.
      • Gear R.B.
      • Belcher S.M.
      Strain specific induction of pyometra and differences in immune responsiveness in mice exposed to 17alpha-ethinyl estradiol or the endocrine disrupting chemical bisphenol A.
      ). Last, in hens, in ovo high dose BPA exposure resulted in abnormal uterine morphology compared with controls (
      • Yigit F.
      • Daglioglu S.
      Histological changes in the uterus of the hens after embryonic exposure to bisphenol A and diethylstilbestrol.
      ). Overall, the results from in vivo studies are suggestive for impaired morphology of the uterus after early life stage BPA exposures at both low and high doses.
      Some of the molecular factors in the uterus that were altered after in vivo BPA exposure include members of the Hoxa family, vascular endothelial growth factor (Vegf), E receptor (ER) alpha and beta (Esr1 and Esr2), and Pgr (
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Lower M.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A alters rat uterine implantation-associated gene expression and reduces the number of implantation sites.
      ,
      • Aldad T.S.
      • Rahmani N.
      • Leranth C.
      • Taylor H.S.
      Bisphenol-A exposure alters endometrial progesterone receptor expression in the nonhuman primate.
      ,
      • Bosquiazzo V.L.
      • Varayoud J.
      • Munoz-de-Toro M.
      • Luque E.H.
      • Ramos J.G.
      Effects of neonatal exposure to bisphenol A on steroid regulation of vascular endothelial growth factor expression and endothelial cell proliferation in the adult rat uterus.
      ,
      • Bromer J.G.
      • Zhou Y.
      • Taylor M.B.
      • Doherty L.
      • Taylor H.S.
      Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response.
      ,
      • Calhoun K.C.
      • Padilla-Banks E.
      • Jefferson W.N.
      • Liu L.
      • Gerrish K.E.
      • Young S.L.
      • et al.
      Bisphenol A exposure alters developmental gene expression in the fetal rhesus macaque uterus.
      ,
      • Kim H.R.
      • Kim Y.S.
      • Yoon J.A.
      • Lyu S.W.
      • Shin H.
      • Lim H.J.
      • et al.
      Egr1 is rapidly and transiently induced by estrogen and bisphenol A via activation of nuclear estrogen receptor-dependent ERK1/2 pathway in the uterus.
      ,
      • Smith C.C.
      • Taylor H.S.
      Xenoestrogen exposure imprints expression of genes (Hoxa10) required for normal uterine development.
      ,
      • Varayoud J.
      • Ramos J.G.
      • Bosquiazzo V.L.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to Bisphenol a impairs the uterine response to ovarian steroids in the adult.
      ). These factors are important for endometrial proliferation and receptivity. In contrast, in utero high dose BPA exposure did not affect expression levels of coding complement component 3 (C3), Pgr, calbindin D9K (S100g), and Vegfa in the adult offspring of rats (
      • Camacho L.
      • Basavarajappa M.S.
      • Chang C.W.
      • Han T.
      • Kobets T.
      • Koturbash I.
      • et al.
      Effects of oral exposure to bisphenol A on gene expression and global genomic DNA methylation in the prostate, female mammary gland, and uterus of NCTR Sprague-Dawley rats.
      ); hence, it is unclear whether they are primary targets for BPA-induced uterine toxicity.
      Findings from in vitro studies using various human cell lines indicate that low dose BPA exposure decreased endothelial cell proliferation (
      • Aghajanova L.
      • Giudice L.C.
      Effect of bisphenol A on human endometrial stromal fibroblasts in vitro.
      ,
      • Bredhult C.
      • Sahlin L.
      • Olovsson M.
      Gene expression analysis of human endometrial endothelial cells exposed to Bisphenol A.
      ) and increased decidualized stromal cell proliferation (
      • Mannelli C.
      • Szostek A.Z.
      • Lukasik K.
      • Carotenuto C.
      • Ietta F.
      • Romagnoli R.
      • et al.
      Bisphenol A modulates receptivity and secretory function of human decidual cells: an in vitro study.
      ) compared with controls. Similarly, high dose BPA exposure decreased endothelial cell proliferation compared with controls (
      • Bredhult C.
      • Backlin B.M.
      • Olovsson M.
      Effects of some endocrine disruptors on the proliferation and viability of human endometrial endothelial cells in vitro.
      ). Some of the potential mechanisms through which BPA may affect cell proliferation in the uterus include alterations in insulin-like growth factor binding protein 1 (IGFBP1), macrophage migration inhibitory factor (MIF), HOXA10, and left right determination factor 1 (LEFTY), steroidogenic receptors (e.g., ESR1, ESR2, PGR), and enzymes (e.g., cytochrome P450, family 11, subfamily a, polypeptide 1; CYP11A1, hydroxysteroid (17-beta) dehydrogenase 1; HSD17B1, hydroxysteroid (17-beta) dehydrogenase 2; HSD17B2), or other hormones (e.g., PRL, LH) (
      • Aghajanova L.
      • Giudice L.C.
      Effect of bisphenol A on human endometrial stromal fibroblasts in vitro.
      ,
      • Aldad T.S.
      • Rahmani N.
      • Leranth C.
      • Taylor H.S.
      Bisphenol-A exposure alters endometrial progesterone receptor expression in the nonhuman primate.
      ,
      • An B.S.
      • Ahn H.J.
      • Kang H.S.
      • Jung E.M.
      • Yang H.
      • Hong E.J.
      • et al.
      Effects of estrogen and estrogenic compounds, 4-tert-octylphenol, and bisphenol A on the uterine contraction and contraction-associated proteins in rats.
      ,
      • Hiyama M.
      • Choi E.K.
      • Wakitani S.
      • Tachibana T.
      • Khan H.
      • Kusakabe K.T.
      • et al.
      Bisphenol-A (BPA) affects reproductive formation across generations in mice.
      ,
      • Mendoza-Rodriguez C.A.
      • Garcia-Guzman M.
      • Baranda-Avila N.
      • Morimoto S.
      • Perrot-Applanat M.
      • Cerbon M.
      Administration of bisphenol A to dams during perinatal period modifies molecular and morphological reproductive parameters of the offspring.
      ,
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      ,
      • Smith C.C.
      • Taylor H.S.
      Xenoestrogen exposure imprints expression of genes (Hoxa10) required for normal uterine development.
      ,
      • Forte M.
      • Mita L.
      • Cobellis L.
      • Merafina V.
      • Specchio R.
      • Rossi S.
      • et al.
      Triclosan and bisphenol A affect decidualization of human endometrial stromal cells.
      ,
      • Mannelli C.
      • Szostek A.Z.
      • Lukasik K.
      • Carotenuto C.
      • Ietta F.
      • Romagnoli R.
      • et al.
      Bisphenol A modulates receptivity and secretory function of human decidual cells: an in vitro study.
      ,
      • Naciff J.M.
      • Khambatta Z.S.
      • Reichling T.D.
      • Carr G.J.
      • Tiesman J.P.
      • Singleton D.W.
      • et al.
      The genomic response of Ishikawa cells to bisphenol A exposure is dose- and time-dependent.
      ). Furthermore, Naciff et al. (
      • Naciff J.M.
      • Khambatta Z.S.
      • Reichling T.D.
      • Carr G.J.
      • Tiesman J.P.
      • Singleton D.W.
      • et al.
      The genomic response of Ishikawa cells to bisphenol A exposure is dose- and time-dependent.
      ) performed a microarray on Ishikawa cells that were cultured with a range of low and high BPA doses (1 nM–100 μM) and found that multiple molecular pathways (e.g., cell organization and biogenesis, proliferation, and intracellular transport) were altered in response to BPA compared with controls.
      In contrast, two studies (
      • Forte M.
      • Mita L.
      • Cobellis L.
      • Merafina V.
      • Specchio R.
      • Rossi S.
      • et al.
      Triclosan and bisphenol A affect decidualization of human endometrial stromal cells.
      ,
      • Helmestam M.
      • Davey E.
      • Stavreus-Evers A.
      • Olovsson M.
      Bisphenol A affects human endometrial endothelial cell angiogenic activity in vitro.
      ) on human cell lines cultured with low and high BPA doses found no effect on proliferation of primary stromal endometrial cells. Differences in cell viability or proliferation may be due to the study design and experimental model. For example, differences in the source of the cells (carcinogenic tissue vs. normal) and differences in the experimental cell lines (primary vs. established/immortal cell line lines such as Ishikawa). Nevertheless, most in vitro studies support the observations reported in these in vivo studies.
      Last, at the end of pregnancy, the uterus needs to contract to induce labor. Uterine contractions are under the control of endogenous hormones such as E2, P, oxytocin, and prostaglandins (PG) (
      • Riemer R.K.
      • Heymann M.A.
      Regulation of uterine smooth muscle function during gestation.
      ). The effects of BPA on uterine contractility were investigated in one study (
      • An B.S.
      • Ahn H.J.
      • Kang H.S.
      • Jung E.M.
      • Yang H.
      • Hong E.J.
      • et al.
      Effects of estrogen and estrogenic compounds, 4-tert-octylphenol, and bisphenol A on the uterine contraction and contraction-associated proteins in rats.
      ) in rats. Findings from this study suggest that BPA exposure decreased uterine contractility and altered transcript and protein levels of contraction-associated factors. Specifically, high dose BPA exposure increased oxytocin and oxytocin receptor, and decreased PG F receptor compared with controls (
      • An B.S.
      • Ahn H.J.
      • Kang H.S.
      • Jung E.M.
      • Yang H.
      • Hong E.J.
      • et al.
      Effects of estrogen and estrogenic compounds, 4-tert-octylphenol, and bisphenol A on the uterine contraction and contraction-associated proteins in rats.
      ). Overall, the current literature suggests that BPA exposure selectively affects uterine cell proliferation and function, depending on the study model. These effects of BPA on uterine function could lead to adverse effects on fertility.

       Estrous Cyclicity

      Estrous cyclicity is crucial for ovulation and the preparation of the uterus for potential implantation. Hence, chemical exposures that disrupt estrous cyclicity can impair fertility. Multiple experimental studies examined the effects of BPA exposure on estrous cyclicity (Table 8). Early neonatal low (
      • Fernandez M.
      • Bianchi M.
      • Lux-Lantos V.
      • Libertun C.
      Neonatal exposure to bisphenol a alters reproductive parameters and gonadotropin releasing hormone signaling in female rats.
      ,
      • Lee S.G.
      • Kim J.Y.
      • Chung J.Y.
      • Kim Y.J.
      • Park J.E.
      • Oh S.
      • et al.
      Bisphenol A exposure during adulthood causes augmentation of follicular atresia and luteal regression by decreasing 17beta-estradiol synthesis via downregulation of aromatase in rat ovary.
      ,
      • Monje L.
      • Varayoud J.
      • Munoz-de-Toro M.
      • Luque E.H.
      • Ramos J.G.
      Exposure of neonatal female rats to bisphenol A disrupts hypothalamic LHRH pre-mRNA processing and estrogen receptor alpha expression in nuclei controlling estrous cyclicity.
      ) and high (
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      ) dose BPA exposure increased or decreased days in estrus and altered cycles in adult mice or rats (70–90 days) compared with controls. In contrast, low dose BPA exposure at earlier time points (51–54 days old) had no effect on estrous cyclicity (
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      ). In rats, in utero low dose (
      • Mendoza-Rodriguez C.A.
      • Garcia-Guzman M.
      • Baranda-Avila N.
      • Morimoto S.
      • Perrot-Applanat M.
      • Cerbon M.
      Administration of bisphenol A to dams during perinatal period modifies molecular and morphological reproductive parameters of the offspring.
      ) and high dose (
      • Adewale H.B.
      • Jefferson W.N.
      • Newbold R.R.
      • Patisaul H.B.
      Neonatal bisphenol-a exposure alters rat reproductive development and ovarian morphology without impairing activation of gonadotropin-releasing hormone neurons.
      ,
      • Delclos K.B.
      • Camacho L.
      • Lewis S.M.
      • Vanlandingham M.M.
      • Latendresse J.R.
      • Olson G.R.
      • et al.
      Toxicity evaluation of bisphenol A administered by gavage to Sprague Dawley rats from gestation day 6 through postnatal day 90.
      ) BPA exposure resulted in irregular estrous cycles in the offspring compared with controls. In addition, studies published by Wang et al. (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ) and Ziv-Gal et al. (
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      ) examined the effects of in utero exposure of low dose BPA on estrous cyclicity in subsequent generations of mice. Interestingly, BPA-induced altered cyclicity was observed in both the F1 and F3 generations, but not in the F2 generation compared with controls. In contrast, other studies reported no effect of in utero low dose BPA exposure or 50 mg/kg/d (i.e., lowest observable adverse effect level) on estrous cyclicity of rats and mice offspring (
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      ,
      • Vigezzi L.
      • Bosquiazzo V.L.
      • Kass L.
      • Ramos J.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to bisphenol A alters the differentiation and functional response of the adult rat uterus to estrogen treatment.
      ,
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      ). Differences in study design and timing of evaluation of estrous cyclicity may explain the disagreement between the results. Overall, neonatal BPA exposure may affect estrous cyclicity in older animals. However, the evidence regarding the effects of in utero BPA exposure on estrous cyclicity is inconclusive. Further studies that examine the effects of in utero BPA exposure on estrous cyclicity and that encompass multiple generations are needed to fully understand the effects of BPA on estrous cyclicity.
      Table 8BPA and estrous cyclicity.
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      RatLong EvansInjectionPND 0–350μg/kg/d, 50 mg/kg/dPost weaning and vaginal openingBy wk, 15 only 33% of females (BPA50 mg/kg) cycled regularly
      • Adewale H.B.
      • Jefferson W.N.
      • Newbold R.R.
      • Patisaul H.B.
      Neonatal bisphenol-a exposure alters rat reproductive development and ovarian morphology without impairing activation of gonadotropin-releasing hormone neurons.
      RatSprague DawleyOral gavageGD 6–birth+

      PND 1–15 or 21
      2.5, 8, 25, 80, 260, 840 μg/kg/d, 2.7, 100, 300 mg/kg/dF1 PND 15, 21, 90, PND 69–90, 150–170 (estrous)BPA300: abnormal cyclicity (PND90 and 150)
      • Delclos K.B.
      • Camacho L.
      • Lewis S.M.
      • Vanlandingham M.M.
      • Latendresse J.R.
      • Olson G.R.
      • et al.
      Toxicity evaluation of bisphenol A administered by gavage to Sprague Dawley rats from gestation day 6 through postnatal day 90.
      RatSprague DawleySubcutaneous injectionPND 1–1050 μg/50 μl, 500 μg/50 μlPND 21

      PND 60–120
      BPA500 caused irregular cycles with more days in estrus, after PND90
      • Fernandez M.
      • Bianchi M.
      • Lux-Lantos V.
      • Libertun C.
      Neonatal exposure to bisphenol a alters reproductive parameters and gonadotropin releasing hormone signaling in female rats.
      RatSprague DawleyOral gavage90 d0.001, 0.1 mg/kg/d30 d after the age of 21 wkExtended estrous phase (2–7 d)
      • Lee S.G.
      • Kim J.Y.
      • Chung J.Y.
      • Kim Y.J.
      • Park J.E.
      • Oh S.
      • et al.
      Bisphenol A exposure during adulthood causes augmentation of follicular atresia and luteal regression by decreasing 17beta-estradiol synthesis via downregulation of aromatase in rat ovary.
      RatWistarDrinking water and lactationGD 6–PND 2110 mg/l (1.2 mg/kg/d)F1 3 mo of age for 4 consecutive weeksIrregular estrous cycles
      • Mendoza-Rodriguez C.A.
      • Garcia-Guzman M.
      • Baranda-Avila N.
      • Morimoto S.
      • Perrot-Applanat M.
      • Cerbon M.
      Administration of bisphenol A to dams during perinatal period modifies molecular and morphological reproductive parameters of the offspring.
      RatWistarSubcutaneous injectionPND 1, 3, 5, and 70.05, 20 mg/kg/dPND 85–100BPA0.05: more time in proestrus-estrus
      • Monje L.
      • Varayoud J.
      • Munoz-de-Toro M.
      • Luque E.H.
      • Ramos J.G.
      Exposure of neonatal female rats to bisphenol A disrupts hypothalamic LHRH pre-mRNA processing and estrogen receptor alpha expression in nuclei controlling estrous cyclicity.
      MouseC57BL6JOral12–15 d (first 3 reproductive cycles)50 μg/kg/d51–54 dNo effect on estrous cyclicity
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      MouseICRSubcutaneous injectionPND 80.1, 1, 10, 100 mg/kgObserved: PND 20–29; euthanized: PND 25, 30, 70BPA100: decreased number of days in estrus
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      RatWistarOral, drinking waterGD 9–birth0.5, 50 μg/kg/dF1: PND 45, 90No effect on estrous cyclicity
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      RatWistarDrinking water + lactationGD 9–PND 210.5 or 50 μg/kg/dF1: PND 90, PND 360No effect on estrous cyclicity
      • Vigezzi L.
      • Bosquiazzo V.L.
      • Kass L.
      • Ramos J.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Developmental exposure to bisphenol A alters the differentiation and functional response of the adult rat uterus to estrogen treatment.
      MouseFVBOralGD 11–birth0.5, 20, 50 μg/kg/dF1 on PND 21PND21: shorter time span between vaginal opening and first estrus (BPA50); BPA0.5 less time in proestrus and estrus and more in diestrus and metestrus; BPA20 shortened estrus
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      MouseCD-1Oral gavageGD 1–PND 2012, 25, 50 mg/kg/dF1 on PND 50No effect on estrous cyclicity
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      MouseCD-1Oral gavagePND 21–4925, 50 mg/kg/dPND 50No effect on estrous cyclicity
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      MouseFVBOral of pregnant dams (F0)GD 11–birth0.5, 20, 50 μg/kg/dF1, F2, F3: 3, 6, 9 moF3: delayed age at first estrus (BPA50)
      • Ziv-Gal A.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on reproductive capacity in several generations of mice.
      Note: BPA = bisphenol A.

       Ovary

      The ovary is required for normal production of ova for fertilization and for production of sex steroid hormones that regulate estrous cyclicity and fertility. Thus, BPA exposures that target the ovary can interfere with fertility. One epidemiological study (
      • Souter I.
      • Smith K.W.
      • Dimitriadis I.
      • Ehrlich S.
      • Williams P.L.
      • Calafat A.M.
      • et al.
      The association of bisphenol-A urinary concentrations with antral follicle counts and other measures of ovarian reserve in women undergoing infertility treatments.
      ) examined the associations between BPA levels and ovarian volume and mature follicle counts (Table 9). Results from this study indicate that urinary BPA exposure was negatively correlated with antral follicle counts in women undergoing IVF treatments.
      Table 9BPA and ovary (epidemiological study).
      Study designStudy populationSample sizeTime of BPA measurementBPA concentrationOutcomeReference no.
      ProspectiveWomen undergoing IVFOverall 209; antral follicle count=154; FSH=120; ovarian volume= 114)Urine: upon entry into the study and at subsequent treatment cycle visits; Ultrasound: 3rd d of an unstimulated menstrual cycleUrinary geometric mean (geometric SD). Antral follicle count = 1.6 (2.0); FSH = 1.7 (2.1); ovarian volume = 1.5 (1.8)BPA not associated with d 3-FSH or ovarian volume; higher urinary BPA concentrations associated with lower antral follicle counts
      • Souter I.
      • Smith K.W.
      • Dimitriadis I.
      • Ehrlich S.
      • Williams P.L.
      • Calafat A.M.
      • et al.
      The association of bisphenol-A urinary concentrations with antral follicle counts and other measures of ovarian reserve in women undergoing infertility treatments.
      Findings from experimental studies indicate that in utero or neonatal low and high dose BPA exposures resulted in abnormal ovarian morphology and histology compared with controls (Table 10). Specifically, BPA exposure increased the number of multi-oocyte follicles (
      • Hunt P.A.
      • Lawson C.
      • Gieske M.
      • Murdoch B.
      • Smith H.
      • Marre A.
      • et al.
      Bisphenol A alters early oogenesis and follicle formation in the fetal ovary of the rhesus monkey.
      ), inhibited germ cell nest breakdown (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ,
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      ,
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ), decreased the number of primordial follicles (
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      ,
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ), increased apoptotic oocytes (
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ), and increased primordial follicular recruitment (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ,
      • Rodriguez H.A.
      • Santambrosio N.
      • Santamaria C.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A reduces the pool of primordial follicles in the rat ovary.
      ). It also affected follicle type distribution by reducing the number of antral follicles and increasing the numbers of primary and secondary follicles (
      • Gamez J.M.
      • Penalba R.
      • Cardoso N.
      • Bernasconi P.S.
      • Carbone S.
      • Ponzo O.
      • et al.
      Exposure to a low dose of bisphenol A impairs pituitary-ovarian axis in prepubertal rats: effects on early folliculogenesis.
      ).
      Table 10BPA and ovary.
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      RatLong EvansSubcutaneous injectionPND 0–350 μg/kg/d, 50 mg/kg/dAfter weaning and vaginal openingAbnormal ovarian morphology: multinucleated and hemorrhagic tissue (BPA50 mg/kg)
      • Adewale H.B.
      • Jefferson W.N.
      • Newbold R.R.
      • Patisaul H.B.
      Neonatal bisphenol-a exposure alters rat reproductive development and ovarian morphology without impairing activation of gonadotropin-releasing hormone neurons.
      MouseFVBOralGD 11–birth0.5, 20, 50 μg/kg/dF1, F2, F3: PND 4, 21PND4: no effect on germ cell nest breakdown or % of primordial follicles; reduced Bcl2 (BPA0.5, F2), oxidative stress, autophagy, and altered gene expression; PND21: some effect on follicle numbers and oxidative stress. Altered expression of apoptotic, steroidogenic, Esr1, Ar, and Igf family genes
      • Berger A.
      • Ziv-Gal A.
      • Cudiamat J.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on the ovaries in multiple generations of mice.
      MouseCD-1Subcutaneous injectionPND 7–1420, 40 μg/kg/dPND 15Accelerated primordial to primary follicle transition
      • Chao H.H.
      • Zhang X.F.
      • Chen B.
      • Pan B.
      • Zhang L.J.
      • Li L.
      • et al.
      Bisphenol A exposure modifies methylation of imprinted genes in mouse oocytes via the estrogen receptor signaling pathway.
      MouseCD-1Subcutaneous injectionPND 5–20 (every 5 d)20, 40 μg/kg/dPND 21Accelerated primordial to primary follicle transition
      • Chao H.H.
      • Zhang X.F.
      • Chen B.
      • Pan B.
      • Zhang L.J.
      • Li L.
      • et al.
      Bisphenol A exposure modifies methylation of imprinted genes in mouse oocytes via the estrogen receptor signaling pathway.
      RatSprague DawleyOral gavageGD 6–birth+

      PND 1–15 or 21
      2.5, 8, 25, 80, 260, 840 μg/kg/d,

      2.7, 100, 300 mg/kg/d
      PND 15, 21, 90, PND 69–90, PND 150–170BPA300: small ovaries with depletion of corpora lutea and antral follicles
      • Delclos K.B.
      • Camacho L.
      • Lewis S.M.
      • Vanlandingham M.M.
      • Latendresse J.R.
      • Olson G.R.
      • et al.
      Toxicity evaluation of bisphenol A administered by gavage to Sprague Dawley rats from gestation day 6 through postnatal day 90.
      HumanIn vitro fertilization patientsGranulosa-lutein cell culture72 h1–10,000 ng/mLEnd of cultureBPA 1,000 and 10,000: decreased cell viability; BPA 100 and 1,000: increased MMP-9; BPA 10,000: decreased MMP-9
      • Dominguez M.A.
      • Petre M.A.
      • Neal M.S.
      • Foster W.G.
      Bisphenol A concentration-dependently increases human granulosa-lutein cell matrix metalloproteinase-9 (MMP-9) enzyme output.
      RatWistarDrinking water + lactationGD 0–PND 213 μg/kg/dPND 30No difference in ovarian weight, higher total follicle number, higher primary, secondary, and lower antral follicle numbers; Increased atresia
      • Gamez J.M.
      • Penalba R.
      • Cardoso N.
      • Bernasconi P.S.
      • Carbone S.
      • Ponzo O.
      • et al.
      Exposure to a low dose of bisphenol A impairs pituitary-ovarian axis in prepubertal rats: effects on early folliculogenesis.
      SwineGranulosa cells culture48 h0.1, 1, 10 μMEnd of cultureNo effect on cell proliferation; VEGF secretion stimulated (BPA1, 10); no effect on oxidative stress
      • Grasselli F.
      • Baratta L.
      • Baioni L.
      • Bussolati S.
      • Ramoni R.
      • Grolli S.
      • et al.
      Bisphenol A disrupts granulosa cell function.
      Non-human primateRhesus macaqueSilastic pumpGD 100–term2.2–3.3 ng/mL serum levelsPND 0Increased number of multi-oocyte follicles, impaired oocyte development (unenclosed oocytes)
      • Hunt P.A.
      • Lawson C.
      • Gieske M.
      • Murdoch B.
      • Smith H.
      • Marre A.
      • et al.
      Bisphenol A alters early oogenesis and follicle formation in the fetal ovary of the rhesus monkey.
      HumanIVF patientsGranulosa-lutein cell culture48 h40, 60, 80, 100 μMEnd of cultureBPA 40–100: inhibited proliferation, decreased FSH induced genes (IGF-1, aromatase) and altered aromatase regulators (GATA4, SF-1, PPARγ)
      • Kwintkiewicz J.
      • Nishi Y.
      • Yanase T.
      • Giudice L.C.
      Peroxisome proliferator-activated receptor-gamma mediates bisphenol A inhibition of FSH-stimulated IGF-1, aromatase, and estradiol in human granulosa cells.
      RatSprague DawleyOral gavage90 d0.001, 0.1 mg/kg/d21 wk oldIncreased apoptosis and CASP3, decreased aromatase expression (granulosa cells)
      • Lee S.G.
      • Kim J.Y.
      • Chung J.Y.
      • Kim Y.J.
      • Park J.E.
      • Oh S.
      • et al.
      Bisphenol A exposure during adulthood causes augmentation of follicular atresia and luteal regression by decreasing 17beta-estradiol synthesis via downregulation of aromatase in rat ovary.
      RatWistarIntraperitoneal injectionPND 28–3510, 40, 160 mg/kgPND 35Decreased follicle numbers, increased atretic follicles; decreased H1FOO and FIGLA(BPA160), increased AMH
      • Li Y.
      • Zhang W.
      • Liu J.
      • Wang W.
      • Li H.
      • Zhu J.
      • et al.
      Prepubertal bisphenol A exposure interferes with ovarian follicle development and its relevant gene expression.
      ZebrafishDanio rerioAquarium water14 d1, 10, 100, 1,000 μg/LEnd of exposureAbnormal ovarian follicles; dose dependent increased atresia and decreased primordial follicles
      • Molina A.M.
      • Lora A.J.
      • Blanco A.
      • Monterde J.G.
      • Ayala N.
      • Moyano R.
      Endocrine-active compound evaluation: qualitative and quantitative histomorphological assessment of zebrafish gonads after bisphenol-A exposure.
      MouseC57BL6JOral12–15 d (during first 3 cycles)50 μg/kg/d51–54 dNo differences in follicle type distribution
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      MouseICRSubcutaneous injectionPND 80.1, 1, 10, 100 mg/kgObserved: PND 20–29; scarified: PND 25, 30, 70All BPA groups: reduced ovarian weight (PND 25, 30)
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      MouseCD-1Subcutaneous injectionGD 9–160.1, 1, 10, 100, 1,000 μg/kg/d18 moOvarian cysts (BPA 1)
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.
      MouseFVBCultured antral follicles24–120 h4.4–440 μM (1–100 μg/mL)End of cultureBPA 440: inhibited follicle growth
      • Peretz J.
      • Gupta R.K.
      • Singh J.
      • Hernandez-Ochoa I.
      • Flaws J.A.
      Bisphenol A impairs follicle growth, inhibits steroidogenesis, and downregulates rate-limiting enzymes in the estradiol biosynthesis pathway.
      MouseFVBCultured antral follicles24–96 h4.4–440 μM (1–100 μg/mL)End of cultureBPA 440: inhibited follicle growth, increased atresia rating, Bcl2, Bax, Cdk4, Ccne1, and Trp53, and decreased Ccnd2
      • Peretz J.
      • Craig Z.R.
      • Flaws J.A.
      Bisphenol A inhibits follicle growth and induces atresia in cultured mouse antral follicles independently of the genomic estrogenic pathway.
      MouseC57BL/6, FVB, CD-1Cultured antral follicles24–120 h4.4–440 μM (1–100 μg/mL)End of cultureAll strains: BPA 440 inhibited follicle growth, increased expression of Cdk4, Ccne1, Trp53, Bax, and Bcl2
      • Peretz J.
      • Flaws J.A.
      Bisphenol A down-regulates rate-limiting Cyp11a1 to acutely inhibit steroidogenesis in cultured mouse antral follicles.
      HumanHOSEpiCCulture3, 24, 48 h0.1, 1, 40 nMEnd of cultureIncreased expression of VEGF-R2
      • Ptak A.
      • Gregoraszczuk E.L.
      Effects of bisphenol A and 17beta-estradiol on vascular endothelial growth factor A and its receptor expression in the non-cancer and cancer ovarian cell lines.
      LambHampshire DownSubcutaneous injectionPND 1–1450 μg/kg/dPND 30PND30: increased primordial-to-primary follicle transition but no difference in total follicle numbers; increased multi-oocyte follicles; increased granulosa and theca cell proliferation, induced atresia in small antral follicles
      • Rivera O.E.
      • Varayoud J.
      • Rodriguez H.A.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A or diethylstilbestrol alters the ovarian follicular dynamics in the lamb.
      LambCorriedale X HampshireSubcutaneous injectionPND 1–140.5, 50 μg/kg/dPND 30 or PND34 after FSH stimulationDecreased number of follicles >2 mm, impaired response to FSH as evident by decreased percent of atretic follicles
      • Rivera O.E.
      • Varayoud J.
      • Rodriguez H.A.
      • Santamaria C.G.
      • Bosquiazzo V.L.
      • Osti M.
      • et al.
      Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs.
      RatWistarSubcutaneous injectionPND 1–70.05, 20 mg/kgPND 8BPA20: Increased primordial follicular recruitment, increased granulosa cell proliferation
      • Rodriguez H.A.
      • Santambrosio N.
      • Santamaria C.G.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A reduces the pool of primordial follicles in the rat ovary.
      RatWistarOral, drinking waterGD 9–birth0.5, 50 μg/kg/dPND 21, 45, or 90Lower ovarian weight; reduced number of growing follicles and inhibited transition of primordial to primary follicles; higher numbers of corpora lutea; increased Fshr (BPA0.5); no difference in Lhcgr
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      MouseC57/Bl6J x CBA/CaCultured pre-antral follicles12 d3, 300 nMEnd of cultureBPA 3: accelerated follicle growth
      • Trapphoff T.
      • Heiligentag M.
      • El Hajj N.
      • Haaf T.
      • Eichenlaub-Ritter U.
      Chronic exposure to a low concentration of bisphenol A during follicle culture affects the epigenetic status of germinal vesicles and metaphase II oocytes.
      SheepSuffolkSubcutaneous injectionGD 30–900.5 mg/kg/dFetal ovaries on GD 65, 90Age-dependent increase in mRNA of 3β1hsd, 3β2hsd, AR, Esr1, Gdf9, IR, mTOR, Pparα, and Igf1r; altered miRNA
      • Veiga-Lopez A.
      • Luense L.J.
      • Christenson L.K.
      • Padmanabhan V.
      Developmental programming: gestational bisphenol-A treatment alters trajectory of fetal ovarian gene expression.
      SheepSuffolkSubcutaneous injectionGD 30-900.05, 0.5, 5 mg/kg/d19 moSimilar number or size of corpora lutea; differences in follicular count trajectories
      • Veiga-Lopez A.
      • Beckett E.M.
      • Abi Salloum B.
      • Ye W.
      • Padmanabhan V.
      Developmental programming: prenatal BPA treatment disrupts timing of LH surge and ovarian follicular wave dynamics in adult sheep.
      MouseFVBOralGD 11–birth0.5, 20, 50 μg/kg/dPND 4, 21PND4: inhibited germ cell nest breakdown, decreased primordial follicles (BPA0.5 and 50); altered levels of apoptotic genes
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      MouseCD-1Oral gavageGD 1–PND 2012, 25, 50 mg/kg/dPND 50Similar number of growing follicles
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      MouseCD-1Oral gavagePND 21–4925, 50 mg/kg/dPND 50Similar number of growing follicles
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      Chinese hamsterV79Cell culture12 or 24 h40, 80, 100, 120 μMEnd of cultureIncreased cell viability (BPA40), cytotoxicity (BPA 80, 100, 120). induced DNA damage; micronucleus (BPA100, 120)
      • Xin L.
      • Lin Y.
      • Wang A.
      • Zhu W.
      • Liang Y.
      • Su X.
      • et al.
      Cytogenetic evaluation for the genotoxicity of bisphenol-A in Chinese hamster ovary cells.
      MouseCD-1OralGD 12.5–PND 18.50.2, 0.04, 0.08 mg/kgGD 15.5, 17.5, 19.5

      PND 3, 5, 7
      BPA0.08: higher percentage of oocytes in cysts, higher oocyte number, and fewer primordial follicle numbers on PND3; decreased Stra8 associated with altered DNA methylation
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      MouseCD-1Cultured neonatal ovariesNot specified10, 100 μM3 d of cultureInhibition of germ cell nest breakdown and reduced primordial follicles (BPA10, 100); increased apoptotic oocytes and increased Bax (BPA100); reduced Nobox (BPA100), Nobox, Lhx8 and protein, Sohlh2, Figla (BPA10, 100); increased Lhx8 methylation
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      FishGobiocypris rarusAquarium water8 mo old15, 50 μg/LAfter 14 or 35 dIncreased ovarian weight (BPA15); no histological effects at 14 d; increased atretic follicles and perinuclear oocytes (BPA50); increased Gdf9, Bmp15 (BPA15)
      • Zhang Y.
      • Yuan C.
      • Qin F.
      • Hu G.
      • Wang Z.
      Molecular characterization of gdf9 and bmp15 genes in rare minnow Gobiocypris rarus and their expression upon bisphenol A exposure in adult females.
      FishGobiocypris rarusAquarium water6 mo old1, 15, 225 μg/LAfter 7 dIncreased ovarian weight (BPA15). increased H2O2 ovarian levels (BPA1 and 225): decreased glutathione
      • Zhang Y.
      • Tao S.
      • Yuan C.
      • Liu Y.
      • Wang Z.
      Non-monotonic dose-response effect of bisphenol A on rare minnow Gobiocypris rarus ovarian development.
      MouseC57BL/6Cultured neonatal ovariesPND 4–140.1, 1, 10 μMEnd of culture<5 d culture: increased primary follicle number and decreased primordial follicle number (BPA10); D 10: decreased primordial follicle number and increased primary follicle number (BPA1 and 10); reduced proliferation (Ki67), apoptosis (Casp3), and activation of the PI3K/Akt pathway
      • Zhao Q.
      • Ma Y.
      • Sun N.X.
      • Ye C.
      • Zhang Q.
      • Sun S.H.
      • et al.
      Exposure to bisphenol A at physiological concentrations observed in Chinese children promotes primordial follicle growth through the PI3K/Akt pathway in an ovarian culture system.
      MouseCD-1Cultured neonatal ovariesPND 0–80.1, 1, 5, 10 μg/mL2, 4, or 8 d of culturePND 4: inhibited germ cell nest breakdown, decreased primordial follicles; random fluctuations in levels of anti-oxidant genes (Gpx, Cat, Gsr); limited effects on apoptotic related genes. PND8: increased ROS production (BPA5) yet post germ cell nest breakdown
      • Zhou C.
      • Wang W.
      • Peretz J.
      • Flaws J.A.
      Bisphenol A exposure inhibits germ cell nest breakdown by reducing apoptosis in cultured neonatal mouse ovaries.
      MouseC57BL/6Cultured antral follicles96 h0.004–438 μMEnd of cultureBPA 110-438: inhibited follicular growth

      BPA 43.8-110: increased Bcl2
      • Ziv-Gal A.
      • Craig Z.R.
      • Wang W.
      • Flaws J.A.
      Bisphenol A inhibits cultured mouse ovarian follicle growth partially via the aryl hydrocarbon receptor signaling pathway.
      MouseAhrtm1Bra;

      C57BL/6 background
      Cultured antral follicles96 h0.004–438 μMEnd of cultureBPA 219-438: inhibited follicular growth
      • Ziv-Gal A.
      • Craig Z.R.
      • Wang W.
      • Flaws J.A.
      Bisphenol A inhibits cultured mouse ovarian follicle growth partially via the aryl hydrocarbon receptor signaling pathway.
      MouseCD-1Subcutaneous injectionPND 7–1420, 40 μg/kg/dPND 15Accelerated primordial to primary follicle transition
      • Chao H.H.
      • Zhang X.F.
      • Chen B.
      • Pan B.
      • Zhang L.J.
      • Li L.
      • et al.
      Bisphenol A exposure modifies methylation of imprinted genes in mouse oocytes via the estrogen receptor signaling pathway.
      MouseCD-1Subcutaneous injectionPND 5–20 (every 5 d)20, 40 μg/kg/dPND 21Accelerated primordial to primary follicle transition
      • Chao H.H.
      • Zhang X.F.
      • Chen B.
      • Pan B.
      • Zhang L.J.
      • Li L.
      • et al.
      Bisphenol A exposure modifies methylation of imprinted genes in mouse oocytes via the estrogen receptor signaling pathway.
      Note: BPA = bisphenol A.
      Molecular analysis revealed that low dose BPA exposure affected levels of genes related to apoptosis. Specifically, BPA increased levels of B-cell leukemia/lymphoma 2 (Bcl2), BCL2-like 1 (Bcl2l1) (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ,
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ). BPA exposure also decreased levels of BCL2-antagonist/killer 1 (Bak1), tumor necrosis factor (TNF) receptor superfamily, member 11b (Tnfrsf11b), TNF receptor superfamily, member 1a (Tnfrsf1a), TNF (ligand) superfamily, member 12 (Tnfsf12), and lymphotoxin B receptor (Ltbr) (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ,
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ). In addition, BPA exposure altered BCL2-associated X protein (Bax) levels by either increasing (
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ) or decreasing (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ) its levels. Differences in the effects of BPA on Bax can result from differences in study designs (e.g., ovarian transplant vs. excised neonatal ovaries).
      Furthermore, BPA exposure decreased expression of factors that control folliculogenesis, such as NOBOX oogenesis homeobox (Nobox) (messenger RNA [mRNA] and protein), LIM homeobox protein 8 (Lhx8) (mRNA and protein), spermatogenesis and oogenesis-specific basic helix-loop-helix 2 (Sohlh2), stimulated by retinoic acid gene 8 (Stra8), DNA meiotic recombinase 1 (Dmc1), REC8 meiotic recombination protein (Rec8), synaptonemal complex protein 3 (Scp3), and folliculogenesis-specific basic helix-loop-helix (Figlα) (
      • Zhang H.Q.
      • Zhang X.F.
      • Zhang L.J.
      • Chao H.H.
      • Pan B.
      • Feng Y.M.
      • et al.
      Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes.
      ,
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ). In addition, BPA exposure prevented DNA methylation in CpG sites of Lhx8, indicating that BPA may impair normal processes of folliculogenesis (
      • Zhang T.
      • Li L.
      • Qin X.S.
      • Zhou Y.
      • Zhang X.F.
      • Wang L.Q.
      • et al.
      Di-(2-ethylhexyl) phthalate and bisphenol A exposure impairs mouse primordial follicle assembly in vitro.
      ) and ovarian dynamics.
      Similar effects of exposure to both low and high doses of BPA during neonatal life on the ovary were observed at older ages/after weaning. Specifically, researchers reported findings such as BPA-induced multinucleated and hemorrhagic tissue (
      • Adewale H.B.
      • Jefferson W.N.
      • Newbold R.R.
      • Patisaul H.B.
      Neonatal bisphenol-a exposure alters rat reproductive development and ovarian morphology without impairing activation of gonadotropin-releasing hormone neurons.
      ), multi-oocyte follicles (
      • Rivera O.E.
      • Varayoud J.
      • Rodriguez H.A.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A or diethylstilbestrol alters the ovarian follicular dynamics in the lamb.
      ), altered follicle-type distribution or numbers (
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      ,
      • Delclos K.B.
      • Camacho L.
      • Lewis S.M.
      • Vanlandingham M.M.
      • Latendresse J.R.
      • Olson G.R.
      • et al.
      Toxicity evaluation of bisphenol A administered by gavage to Sprague Dawley rats from gestation day 6 through postnatal day 90.
      ,
      • Chao H.H.
      • Zhang X.F.
      • Chen B.
      • Pan B.
      • Zhang L.J.
      • Li L.
      • et al.
      Bisphenol A exposure modifies methylation of imprinted genes in mouse oocytes via the estrogen receptor signaling pathway.
      ,
      • Gamez J.M.
      • Penalba R.
      • Cardoso N.
      • Bernasconi P.S.
      • Carbone S.
      • Ponzo O.
      • et al.
      Exposure to a low dose of bisphenol A impairs pituitary-ovarian axis in prepubertal rats: effects on early folliculogenesis.
      ,
      • Li Y.
      • Zhang W.
      • Liu J.
      • Wang W.
      • Li H.
      • Zhu J.
      • et al.
      Prepubertal bisphenol A exposure interferes with ovarian follicle development and its relevant gene expression.
      ,
      • Molina A.M.
      • Lora A.J.
      • Blanco A.
      • Monterde J.G.
      • Ayala N.
      • Moyano R.
      Endocrine-active compound evaluation: qualitative and quantitative histomorphological assessment of zebrafish gonads after bisphenol-A exposure.
      ,
      • Rivera O.E.
      • Varayoud J.
      • Rodriguez H.A.
      • Munoz-de-Toro M.
      • Luque E.H.
      Neonatal exposure to bisphenol A or diethylstilbestrol alters the ovarian follicular dynamics in the lamb.
      ,
      • Rivera O.E.
      • Varayoud J.
      • Rodriguez H.A.
      • Santamaria C.G.
      • Bosquiazzo V.L.
      • Osti M.
      • et al.
      Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs.
      ,
      • Veiga-Lopez A.
      • Beckett E.M.
      • Abi Salloum B.
      • Ye W.
      • Padmanabhan V.
      Developmental programming: prenatal BPA treatment disrupts timing of LH surge and ovarian follicular wave dynamics in adult sheep.
      ), reduced ovarian weight (
      • Santamaria C.
      • Durando M.
      • Munoz de Toro M.
      • Luque E.H.
      • Rodriguez H.A.
      Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A.
      ,
      • Nah W.H.
      • Park M.J.
      • Gye M.C.
      Effects of early prepubertal exposure to bisphenol A on the onset of puberty, ovarian weights, and estrous cycle in female mice.
      ), and ovarian cysts (
      • Newbold R.R.
      • Jefferson W.N.
      • Padilla-Banks E.
      Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.
      ) compared with controls. Molecular analysis revealed that high dose BPA exposure decreased the expression of Figla and oocyte-specific histone H1 variant (H1f00), and increased the levels of antimüllerian hormone (Amh) genes (
      • Li Y.
      • Zhang W.
      • Liu J.
      • Wang W.
      • Li H.
      • Zhu J.
      • et al.
      Prepubertal bisphenol A exposure interferes with ovarian follicle development and its relevant gene expression.
      ). In addition, Lee et al. (
      • Lee S.G.
      • Kim J.Y.
      • Chung J.Y.
      • Kim Y.J.
      • Park J.E.
      • Oh S.
      • et al.
      Bisphenol A exposure during adulthood causes augmentation of follicular atresia and luteal regression by decreasing 17beta-estradiol synthesis via downregulation of aromatase in rat ovary.
      ) reported that low dose BPA increased apoptosis in ovarian follicles that was coupled with increased levels of the apoptotic protein caspase-3. Hence, in rodents, BPA affects ovarian development and dynamics by molecular pathways that involve apoptosis, folliculogenesis, and oocyte-specific factors.
      Similarly, in fish, low dose BPA exposure increased ovarian weight, increased levels of hydrogen peroxide, and decreased glutathione levels compared with controls, indicating that BPA may alter the oxidative stress mechanism in the ovary (
      • Zhang Y.
      • Tao S.
      • Yuan C.
      • Liu Y.
      • Wang Z.
      Non-monotonic dose-response effect of bisphenol A on rare minnow Gobiocypris rarus ovarian development.
      ). Another study in fish found that low dose BPA exposure increased ovarian weight, atretic follicles, perinuclear oocytes, and expression of factors involved in folliculogenesis (Gdf9 and Bmp15) compared with controls (
      • Zhang Y.
      • Yuan C.
      • Qin F.
      • Hu G.
      • Wang Z.
      Molecular characterization of gdf9 and bmp15 genes in rare minnow Gobiocypris rarus and their expression upon bisphenol A exposure in adult females.
      ).
      Other studies in mice found no effect on follicle type distribution in the adult ovary after low dose BPA exposure (
      • Moore-Ambriz T.R.
      • Acuna-Hernandez D.G.
      • Ramos-Robles B.
      • Sanchez-Gutierrez M.
      • Santacruz-Marquez R.
      • Sierra-Santoyo A.
      • et al.
      Exposure to bisphenol A in young adult mice does not alter ovulation but does alter the fertilization ability of oocytes.
      ,
      • Xi W.
      • Lee C.K.
      • Yeung W.S.
      • Giesy J.P.
      • Wong M.H.
      • Zhang X.
      • et al.
      Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus-pituitary-gonadal axis of CD-1 mice.
      ). However, it is possible that BPA did not affect ovarian follicle distribution because of the timing of BPA exposure and differences in study design. Furthermore, some of the effects of BPA exposure on the ovary do not persist in subsequent generations. Wang et al. (
      • Wang W.
      • Hafner K.S.
      • Flaws J.A.
      In utero bisphenol A exposure disrupts germ cell nest breakdown and reduces fertility with age in the mouse.
      ) reported that in utero low dose BPA exposure inhibited germ cell nest breakdown in the F1 generation of mice compared with controls. However, these changes were not observed in the subsequent generations examined by Berger et al. (
      • Berger A.
      • Ziv-Gal A.
      • Cudiamat J.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on the ovaries in multiple generations of mice.
      ). Furthermore, BPA exposure caused several generation-specific differences in gene expression, but not all were transgenerational (i.e., genes related to oxidative stress, autophagy, and apoptosis) (
      • Berger A.
      • Ziv-Gal A.
      • Cudiamat J.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on the ovaries in multiple generations of mice.
      ). Interestingly, BPA-induced changes in steroidogenic genes and Esr1, androgen receptor (Ar), and insulin-like growth factor (Igf) family genes were suggested to be carried transgenerationally (
      • Berger A.
      • Ziv-Gal A.
      • Cudiamat J.
      • Wang W.
      • Zhou C.
      • Flaws J.A.
      The effects of in utero bisphenol A exposure on the ovaries in multiple generations of mice.
      ). It is possible that the changes in the genes related to oxidative stress and apoptosis are activated in an acute manner and thus, effects on these factors were not carried into the subsequent generations. In contrast, steroidogenic factors are crucial to the function of the ovary (as an endocrine organ) and thus some of BPA effects on these factors were carried into the subsequent generations. Overall, these experiments provide strong evidence that BPA acts through mechanisms related to apoptosis, folliculogenesis, and oxidative status.
      In mice, in vitro studies (
      • Zhao Q.
      • Ma Y.
      • Sun N.X.
      • Ye C.
      • Zhang Q.
      • Sun S.H.
      • et al.
      Exposure to bisphenol A at physiological concentrations observed in Chinese children promotes primordial follicle growth through the PI3K/Akt pathway in an ovarian culture system.
      ,
      • Zhou C.
      • Wang W.
      • Peretz J.
      • Flaws J.A.
      Bisphenol A exposure inhibits germ cell nest breakdown by reducing apoptosis in cultured neonatal mouse ovaries.
      ) of isolated neonatal ovaries indicate that high dose BPA exposure inhibited germ cell nest breakdown and accelerated primordial follicle recruitment compared with controls, similar to some of the observations in in vivo studies. Specifically, BPA exposure decreased levels antigen KI-67 (Ki67), TNF receptor superfamily member 6 (Fas), and caspases (Casp3 and 8). Furthermore, BPA increased levels of Bcl2 and factors related to the phosphatidylinositol 3-kinase/thymoma viral proto-oncogene (PI3K/Akt) signaling pathway (
      • Zhao Q.
      • Ma Y.
      • Sun N.X.
      • Ye C.
      • Zhang Q.
      • Sun S.H.
      • et al.
      Exposure to bisphenol A at physiological concentrations observed in Chinese children promotes primordial follicle growth through the PI3K/Akt pathway in an ovarian culture system.
      ,
      • Zhou C.
      • Wang W.
      • Peretz J.
      • Flaws J.A.
      Bisphenol A exposure inhibits germ cell nest breakdown by reducing apoptosis in cultured neonatal mouse ovaries.
      ). In sheep fetal ovaries, low dose BPA exposure resulted in an age-dependent increase in expression of steroidogenic genes, mammalian target of rapamycin (mTor), peroxisome proliferator-activated receptor (Pparα), and Igf1r compared with controls (
      • Veiga-Lopez A.
      • Luense L.J.
      • Christenson L.K.
      • Padmanabhan V.
      Developmental programming: gestational bisphenol-A treatment alters trajectory of fetal ovarian gene expression.
      ). The overall findings suggest that BPA may act through mechanisms that are related to follicle dynamics and apoptosis. Furthermore, studies suggest that BPA exposure may act through mechanisms involving altered microRNA levels (
      • Veiga-Lopez A.
      • Luense L.J.
      • Christenson L.K.
      • Padmanabhan V.
      Developmental programming: gestational bisphenol-A treatment alters trajectory of fetal ovarian gene expression.
      ). BPA down-regulated miR-137 may decrease sex steroid hormone synthesis (
      • Sirotkin A.V.
      • Ovcharenko D.
      • Grossmann R.
      • Laukova M.
      • Mlyncek M.
      Identification of microRNAs controlling human ovarian cell steroidogenesis via a genome-scale screen.
      ) and miR-765 may be associated with premature ovarian failure (
      • Yang X.
      • Zhou Y.
      • Peng S.
      • Wu L.
      • Lin H.Y.
      • Wang S.
      • et al.
      Differentially expressed plasma microRNAs in premature ovarian failure patients and the potential regulatory function of mir-23a in granulosa cell apoptosis.
      ,
      • Zhou Y.
      • Zhu Y.
      • Zhang S.
      • Wang H.
      • Wang S.
      • Yang X.
      MicroRNA expression profiles in premature ovarian failure patients and its potential regulate functions.
      ). Additional findings included variable levels of microRNAs related to insulin signaling, without changing levels of microRNA processing enzymes (
      • Veiga-Lopez A.
      • Luense L.J.
      • Christenson L.K.
      • Padmanabhan V.
      Developmental programming: gestational bisphenol-A treatment alters trajectory of fetal ovarian gene expression.
      ).
      In vitro studies of isolated mouse ovarian follicles indicate that high dose BPA exposure selectively inhibited antral follicular growth (
      • Peretz J.
      • Gupta R.K.
      • Singh J.
      • Hernandez-Ochoa I.
      • Flaws J.A.
      Bisphenol A impairs follicle growth, inhibits steroidogenesis, and downregulates rate-limiting enzymes in the estradiol biosynthesis pathway.
      ,
      • Peretz J.
      • Craig Z.R.
      • Flaws J.A.
      Bisphenol A inhibits follicle growth and induces atresia in cultured mouse antral follicles independently of the genomic estrogenic pathway.
      ,
      • Peretz J.
      • Flaws J.A.
      Bisphenol A down-regulates rate-limiting Cyp11a1 to acutely inhibit steroidogenesis in cultured mouse antral follicles.
      ,
      • Ziv-Gal A.
      • Craig Z.R.
      • Wang W.
      • Flaws J.A.
      Bisphenol A inhibits cultured mouse ovarian follicle growth partially via the aryl hydrocarbon receptor signaling pathway.
      ), but increased preantral follicle growth (
      • Trapphoff T.
      • Heiligentag M.
      • El Hajj N.
      • Haaf T.
      • Eichenlaub-Ritter U.
      Chronic exposure to a low concentration of bisphenol A during follicle culture affects the epigenetic status of germinal vesicles and metaphase II oocytes.
      ) compared with controls. Molecular analysis revealed that BPA exposure affected the expression of genes related to the cell cycle, apoptosis, and steroidogenesis (
      • Peretz J.
      • Gupta R.K.
      • Singh J.
      • Hernandez-Ochoa I.
      • Flaws J.A.
      Bisphenol A impairs follicle growth, inhibits steroidogenesis, and downregulates rate-limiting enzymes in the estradiol biosynthesis pathway.
      ,
      • Peretz J.
      • Craig Z.R.
      • Flaws J.A.
      Bisphenol A inhibits follicle growth and induces atresia in cultured mouse antral follicles independently of the genomic estrogenic pathway.
      ,
      • Peretz J.
      • Flaws J.A.
      Bisphenol A down-regulates rate-limiting Cyp11a1 to acutely inhibit steroidogenesis in cultured mouse antral follicles.
      ,
      • Ziv-Gal A.
      • Craig Z.R.
      • Wang W.
      • Flaws J.A.
      Bisphenol A inhibits cultured mouse ovarian follicle growth partially via the aryl hydrocarbon receptor signaling pathway.
      ). Specifically, BPA exposure increased Bcl2, cyclin-dependent kinase 4 (Cdk4), cyclin E1 (Ccne1), transformation-related protein 53 (Trp53), Bax, and down-regulated cyclin D2 (Ccnd2). In short-term cultures (up to 24 hours) of Chinese hamster ovarian cells, high doses of BPA selectively increased cell viability, increased cytotoxicity, and induced DNA damage and the appearance of micronuclei (
      • Xin L.
      • Lin Y.
      • Wang A.
      • Zhu W.
      • Liang Y.
      • Su X.
      • et al.
      Cytogenetic evaluation for the genotoxicity of bisphenol-A in Chinese hamster ovary cells.
      ). In short-term cultures (3–48 hours) of human ovarian cells, low dose BPA increased expression of VEGF-R2 (
      • Ptak A.
      • Gregoraszczuk E.L.
      Effects of bisphenol A and 17beta-estradiol on vascular endothelial growth factor A and its receptor expression in the non-cancer and cancer ovarian cell lines.
      ). In short-term cultures (48 hours) of human granulosa (GC) cells and lutein cells, high dose BPA inhibited cell proliferation and decreased levels of IGF-1, aromatase, GATA-binding protein 4 (GATA4), steroidogenic factor-1 (SF-1), and PPARγ (
      • Kwintkiewicz J.
      • Nishi Y.
      • Yanase T.
      • Giudice L.C.
      Peroxisome proliferator-activated receptor-gamma mediates bisphenol A inhibition of FSH-stimulated IGF-1, aromatase, and estradiol in human granulosa cells.
      ). In contrast, in short-term porcine GC cultures (48 hours), high dose BPA did not affect cell proliferation or expression of oxidative stress genes (
      • Grasselli F.
      • Baratta L.
      • Baioni L.
      • Bussolati S.
      • Ramoni R.
      • Grolli S.
      • et al.
      Bisphenol A disrupts granulosa cell function.
      ). Similar concentrations of BPA during longer culture times (72 hours) decreased viability and disrupted matrix metallopeptidase 9 (MMP-9) secretion in human GCs (
      • Dominguez M.A.
      • Petre M.A.
      • Neal M.S.
      • Foster W.G.
      Bisphenol A concentration-dependently increases human granulosa-lutein cell matrix metalloproteinase-9 (MMP-9) enzyme output.
      ). It is plausible that some of BPA-mediated effects can be detected only at the end of longer culture times, or in a species specific manner.
      Overall, current studies indicate that BPA affects the ovary, mainly during the ovarian developmental window as well as in early neonatal life through multiple pathways that include cell cycle, apoptosis, oxidative stress, and proliferation. More epidemiological studies are warranted to better understand the specific associations of BPA exposure and ovarian outcomes in women. Furthermore, additional experimental studies are warranted to better understand the specific mechanisms of action and the specific effects of low and high doses of BPA on the ovary.

       Hypothalamic-pituitary-ovarian Axis

      Overall, reproductive function is dependent on the hypothalamic-pituitary-ovarian axis. After sexual maturation, coordinated feedback loops along the hypothalamic-pituitary-ovarian axis control the ability of the mammalian female to ovulate and to prepare the reproductive organs to support potential pregnancy. In the hypothalamus, sex steroid hormones (E2 and P) activate the kisspeptin neurons that in turn relay the secretion of GnRH. The GnRH stimulates the anterior pituitary to secrete gonadotrophic hormones (FSH and LH). The FSH and LH act on the ovary to support folliculogenesis. Increased levels of ovarian sex steroid hormones feedback to the hypothalamic kisspeptin neurons to induce the LH surge, which is needed for ovulation. Therefore, any alteration in proper levels/function of the hypothalamic-pituitary axis including the kisspeptin neurons can alter female fertility. The following sections describe the current data on the effects of BPA on the hypothalamus (Table 11), pituitary (Table 11), and gonadotrophic hormones (Table 12, Table 13).
      Table 11BPA and hypothalamic-pituitary-ovarian axis.
      SourceStrainExposure routeTime of exposureDosesTime of observationOutcomeReference no.
      SheepSuffolkSubcutaneous injectionGD 30–905 mg/kg/dF1: OVX at 21 mo, testing at 23–26 moNo effect on steroid feedback and/or increased pituitary responsiveness to GnRH
      • Abi Salloum B.
      • Steckler T.L.
      • Herkimer C.
      • Lee J.S.
      • Padmanabhan V.
      Developmental programming: impact of prenatal exposure to bisphenol-A and methoxychlor on steroid feedbacks in sheep.
      MouseMixed FVB X C57BL/6OralGD 10.5–18.50.5, 50 μg/kg/dBirthIncreased number of pituitary mKi67-immunoreactive cells, increased gonadotroph cell number (LHβ, FSHβ positive); increased Lhβ and Fshβ (BPA0.5); Decreased Lhβ and Fshβ, Nr5a1 (BPA50); decreased Gnrhr (BPA0.5, 50); no effect on hormone synthesis by pituitary cells
      • Brannick K.E.
      • Craig Z.R.
      • Himes A.D.
      • Peretz J.R.
      • Wang W.
      • Flaws J.A.
      • et al.
      Prenatal exposure to low doses of bisphenol A increases pituitary proliferation and gonadotroph number in female mice offspring at birth.
      RatLong EvansSubcutaneous injectionPND 0–250 μg/kg/d, 50 mg/kg/dPND 4 or 10PND4: increased Esr1, no effect on Esr2, diminished Kiss1; PND10: Esr1 decreased to male typical levels, decreased/eliminated Esr2, diminished Kiss1
      • Cao J.
      • Mickens J.A.
      • McCaffrey K.A.
      • Leyrer S.M.
      • Patisaul H.B.
      Neonatal Bisphenol A exposure alters sexually dimorphic gene expression in the postnatal rat hypothalamus.
      RatLong EvansSubcutaneous injectionPND 0–250 μg/kg/d, 50 mg/kg/dPND 4 or 10Altered Esr2 expression and reversed sex differences in expression
      • Cao J.
      • Joyner L.
      • Mickens J.A.
      • Leyrer S.M.
      • Patisaul H.B.
      Sex-specific Esr2 mRNA expression in the rat hypothalamus and amygdala is altered by neonatal bisphenol A exposure.
      RatSprague-DawleyOral gavageGD 6–PND 212.5, 25.0 μg/kg/dPND 21No effect on density of anteroventral periventricular nucleus tyrosine hydroxylase immunoreactivity
      • Ferguson S.A.
      • Paule M.G.
      • He Z.
      Pre- and postnatal bisphenol A treatment does not alter the number of tyrosine hydroxylase-positive cells in the anteroventral periventricular nucleus (AVPV) of weanling male and female rats.
      MouseBALB/cOralGD 0–192, 20, 200 μg/kg/dPND 28BPA20 altered methylation patterns in the hypothalamus
      • Kundakovic M.
      • Gudsnuk K.
      • Franks B.
      • Madrid J.
      • Miller R.L.
      • Perera F.P.
      • et al.
      Sex-specific epigenetic disruption and behavioral changes following low-dose in utero bisphenol A exposure.
      SheepSuffolkSubcutaneous injectionGD 30–905 mg/kg/dAdult prior to onset of pre-ovulatory LH surgeDecreased hypothalamic levels of GnRH; increased ESR1; decreased ESR2 (medial preoptic area)
      • Mahoney M.M.
      • Padmanabhan V.
      Developmental programming: impact of fetal exposure to endocrine-disrupting chemicals on gonadotropin-releasing hormone and estrogen receptor mRNA in sheep hypothalamus.
      RatWistarSubcutaneous injectionPND 1, 3, 5, and 70.05, 20 mg/kg/dPND 100Anteroventral periventricular nucleus expression of Esr1 increased (BPA0.05, 20), PR decreased (BPA0.05); arcuate nucleus expression of Esr1 decreased (BPA0.05, 20), no effect on PR
      • Monje L.
      • Varayoud J.
      • Munoz-de-Toro M.
      • Luque E.H.
      • Ramos J.G.
      Exposure of neonatal female rats to bisphenol A disrupts hypothalamic LHRH pre-mRNA processing and estrogen receptor alpha expression in nuclei controlling estrous cyclicity.
      RatWistarSubcutaneous injectionPND 1–5100, 500 μg/kg/dPND 30Decreased hypothalamic Kiss1
      • Navarro V.M.
      • Sanchez-Garrido M.A.
      • Castellano J.M.
      • Roa J.
      • Garcia-Galiano D.
      • Pineda R.
      • et al.
      Persistent impairment of hypothalamic KiSS-1 system after exposures to estrogenic compounds at critical periods of brain sex differentiation.
      RatLong EvansSubcutaneous injectionPND 0–350 μg/kg/d, 50 mg/kg/dAfter weaning and vaginal openingBPA 50 mg/kg reduced density of hypothalamic kisspeptin immunoreactive fibers; more profound in arcuate nucleus
      • Patisaul H.B.
      • Todd K.L.
      • Mickens J.A.
      • Adewale H.B.
      Impact of neonatal exposure to the ERalpha agonist PPT, bisphenol-A or phytoestrogens on hypothalamic kisspeptin fiber density in male and female rats.
      FishTransgenic zebrafishAquarium0.1, 1, 10, 100, 1,000 μg/L25, 120 h after fertilizationSelective increase of Kiss1, Kiss1r, Gnrh3, Lhβ, Fshβ, synaptic vesicle protein-2 (Sv2)
      • Qiu W.
      • Zhao Y.
      • Yang M.
      • Farajzadeh M.
      • Pan C.
      • Wayne N.L.
      Actions of bisphenol A and bisphenol S on the reproductive neuroendocrine system during early development in zebrafish.
      MouseICROralProestrus of 4th/5th estrous20 μg/kg/d6 h after administrationElevated plasma Gnrh; Increased Kiss1 in anteroventral periventricular nucleus
      • Wang X.
      • Chang F.
      • Bai Y.
      • Chen F.
      • Zhang J.
      • Chen L.
      Bisphenol A enhances kisspeptin neurons in anteroventral periventricular nucleus of female mice.
      MouseICRInjection into right lateral ventricleProestrus of 4th/5th estrous0.02, 0.2, 2, 20, 200 nM/3 μL6 h after administrationAnteroventral periventricular nucleus -Kiss1 altered (BPA EC50 2.754 nM) and arcuate nucleus (BPA>20nM); BPA increased Gnrh mRNA, but effect blocked by pretreatment with GPR54 blocker