P-747 Chromosomal mosaic characteristics among women under IVF treatment: multicentric study of 2282 mosaic embryos diagnosed by preimplantation genetic testing with trophectoderm biopsy

Abstract Study question Which chromosomal mosaic features do women under IVF treatment show? Summary answer Single aneuploidies were the most represented among embryos and their frequency as well level of mosaicism increased in older women. What is known already Chromosomal are characterised by presence chromosomally different cell lines within same embryo. We previously demonstrated that reproductive potential affected complexity number aneuploid cells present trophectoderm (TE) biopsy. Although with introduction next generation sequencing (NGS) constitution human have been elucidated, only limited characterised. Therefore, we performed a larger-scale multicenter study on to examine patterns prevalence chromosome specific mosaicisms TE samples. design, size, duration This retrospective cohort from May 2019 2021 20200 obtained 5770 treatment. From this cohort, 2280 analysed. All cultured blastocyst stage; biopsy was Day-5 development or Day-6/7 for slow growing embryos. Participants/materials, setting, methods biopsies underwent comprehensive screening (CCS) utilizing validated NGS. classified if they had 20%-80% abnormal cells. For statistical analysis, divided in: single whole-chromosome trisomy, double trisomies, monosomy, monosomies complex aneuploidy (more than two aneuploidies) groups. In addition, single, segmental evaluated. each group, trend related maternal age examined. Main results role chance Among 2282 (whole-chromosome segmental) represented(52%) followed complex(36%) ones(14%). When based types aneuploidies, frequent(34%) segmental(31%), monosomies(14%), trisomy(12%). The more chromosomes trisomies 16(7%), 19 (7%), 21 22(6%). Monosomy involved mainly 7(8%), 22(7%). Chromosomes 1, 5(9%), 9(8%) targeted duplication while deletion mostly 1(11%), 2(13%) X(8%). percentage Limitations, reasons caution observational, demonstrating relative but not offering any direct insight into clinical relevance findings. More data must be before approach can evaluated an additional tool choose transfer. Wider implications findings provides large dataset offers detailed information distribution general population Trial registration Not applicable