en 39157285 <p>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.<br /> 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.<br /> 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.<br /> 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.</p> Aneuploidy, Biopsy, Blastocyst, Cleavage stage, Preimplantation 56 60 https://www.jri.ir/article/140209 https://www.jri.ir/documents/fullpaper/en/140209.pdf MasoodBazrgarDepartment of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iranmbazrgar@royaninstitute.org112084RoxanaKariminejadKariminejad-Najmabadi Pathology and Genetics Center, Tehran, Iran112086PoopakEftekhari-YazdiDepartment of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran112087HamidGourabiDepartment of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran112085