Evaluating the Plausibility of Euploid Embryos Transfer on Day-5 by Reanalysis of Day-3 Single Aneuploid Embryos: A Case Series

Background: during preimplantation development, single aneuploidies are more commonly tolerated than complex aneuploidies. some studies have reported that blastocysts with aneuploid karyotypes on day-3 embryo biopsy can exhibit a normal karyotype on day-5 rebiopsy, suggesting that single aneuploidies may have a higher likelihood of presenting a normal karyotype on day-5. the purpose of the current study was to assess the benefit of reanalyzing the karyotypes of day-3 single aneuploid embryos on day-5. methods: day-3 and day-5 biopsies of preimplantation embryos were subjected to array comparative genomic hybridization (acgh). a proof of concept case series study was conducted involving 13 day-5 embryos from 4 couples across 3 art centers, collected between october 2019 and june 2020. each center provided one normal embryo and 3-4 embryos with single aneuploidy based on day-3 acgh results. the karyotype of each day-5 embryo was compared with its corresponding day-3 karyotype. results: among the 10 embryos with single aneuploidy on day-3, 3 (30%) exhibited discordant karyotypes on day-5, while the remaining 7 single aneuploid embryos and 3 normal embryos maintained the same karyotype from day-3 to day-5. none of the day-3 single aneuploid embryos displayed a normal karyotype on day-5. conclusion: contrary to previous reports suggesting the potential correction of single aneuploidies in some embryos, the findings of this study did not support such a possibility in the analyzed embryos. genomic reanalysis of day-3 single aneuploid embryos on day-5 does not appear to be a reliable method for identifying euploid embryos suitable for transfer.