Don’t wait to freeze your eggs: as age increases significantly more eggs are needed to generate a normal embryo


      In recent years the outcomes after oocyte cryopreservation (OC) have been significantly improved due to vitrification. However, most of the literature on OC outcomes is in women under the age of 35. Little is known about the usefulness of OC as a means of fertility preservation in older women. The aim of this study was to calculate the number of oocytes a woman would need to have retrieved in order to create a single euploid embryo based on her age.


      Retrospective data analysis from a single private fertility clinic.

      Materials and Methods

      Data for all patients (n=350) undergoing in vitro fertilization for gender selection through preimplantation genetic screening (PGS) by array comparative genomic hybridization between 1/2008 and 3/2014 were analyzed. Patients undergoing PGS for gender selection were used as a proxy for fertile couples. The subjects were divided into 5 groups based on the SART age groups. The total number of oocytes retrieved, number of embryos available for biopsy, and number of euploid embryos were compared between the groups using an ANOVA. Within each age group we calculated the number of retrieved oocytes needed to generate a single euploid embryo by dividing the mean number of oocytes retrieved by the mean number of euploid embryos. The calculation thus took into account the women who did not make any normal embryos.


      The numbers (mean ± SE) of oocytes retrieved, embryos available for biopsy, and euploid embryos decreased significantly with advancing age.
      Tabled 1ICSI Outcomes
      MICTRP value
      Oocyte injected262238
      Oocyte Fertilized205146
      N°Emb D2205142
      Grade 1Emb(%)117(57%)62(44%)<0.0001
      Grade 2Emb(%)60(29%)59(42%)
      Grade 3Emb(%)19(9%)40(28%)<0.0001
      N° BL5341
      BL rate40%38%
      TOT ET8760
      PURE ET46180.0047


      The average number of oocytes that would be expected to yield a normal embryo increases significantly after the age of 37 and almost exponentially after the age of 42. A 42-year-old would need to undergo approximately 11 stimulation cycles in order to produce the 103 oocytes that would be expected to generate a single normal embryo. Women should be made aware of the challenges of fertility preservation with advancing age so that they can seek treatment at ages that will allow them the greatest opportunity for success.