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Rebiopsy and preimplanation genetic screening (PGS) reanalysis demonstrate the majority of originally “no diagnosis” embryos are euploid with comparable pregnancy rates

      Objective

      The genetic viability and clinical outcomes of embryos that undergo PGS and do not receive a genetics diagnosis is not clear. We have previously demonstrated that over half of these “no diagnosis” embryos are euploid. The aim of this study is assess the clinical value of these re-biopsied embryos in an expanded cohort.

      Design

      Retrospective cohort study from a single large private fertility clinic.

      Materials and Methods

      Patients who underwent PGS from January 2010 to February 2015 were analyzed for cycles that resulted in at least 1 embryo without a diagnosis. These cycles were then examined to assess whether embryo re-biopsy was performed. Initial biopsy was performed on either day 3 or day 5, and re-biopsy was performed on either day 5 or day 6. Information on fresh versus frozen re-biopsy, embryo diagnosis, embryo transfer, and pregnancy rate was collected. Fisher’s exact test was used for statistical analysis.

      Results

      There were 1,523 in-vitro fertilization (IVF) cycles with PGS during this time period. Of these cycles, 132 (8.7%) had at least one embryo with “no diagnosis”. Overall, there were 183 embryos (2.0%) with “no diagnosis”, and 52 (28%) of those embryos underwent re-biopsy. Forty-seven of these embryos were initially biopsied at the blastocyst stage, and 5 were initially biopsied on day 3. At the time of repeat biopsy, 43 of the embryos (83%) were fresh and 9 (17%) had undergone a thaw after initial cryopreservation. Of the 52 embryos that were re-biopsied and reanalyzed, 96% were assigned a genetic diagnosis. There was no difference in the likelihood of obtaining a diagnosis between fresh and cryopreserved-thawed re-biopsied embryo (95.3% versus 100%, p=1.00). Twenty-five re-biopsied embryos were diagnosed as euploid (53%). Fourteen of these chromosomally normal re-biopsied embryos were transferred, and the clinical outcome of eight of these embryos that were replaced as single embryo transfers (SET) could be accurately assessed. The pregnancy rate after SET was 37.5% (3/8) for all re-biopsied embryos, and 60% (3/5) for only initial blastocyst biopsy embryos.

      Conclusions

      Embryos that have undergone PGS with a “no diagnosis” result can be safely and successfully re-biopsied fresh as well as after cryopreservation and thaw. A chromosomal diagnosis was successfully assigned in 96% of re-biopsied embryos. Over half of these re-biopsied embryos were diagnosed as euploid after re-analysis with aCGH. Although the numbers are small, pregnancy rates after transfer of euploid re-biopsied embryos are comparable to single-biopsied euploid embryo transfer rates in the literature, demonstrating the high clinical utility of these embryos.