[Embryo euploidy rates and pregnancy outcomes in carriers of chromosomal structural rearrangements undergoing preimplantation genetic testing].

Objective: To investigate the embryonic chromosomal status and pregnancy outcomes of carriers of chromosomal structural rearrangements undergoing preimplantation genetic testing for structural rearrangement (PGT-SR), and to analyze the influence of factors on PGT-SR results. Methods: A retrospective analysis was conducted on clinical data from 700 couples with chromosomal structural rearrangements [including reciprocal translocation (RecT), Robertsonian translocation (RobT), and inversion] who underwent PGT-SR at Northwest Women's and Children's Hospital between 2019 and 2024. A total of 3 471 blastocysts were biopsied. A control group of 261 couples (1 282 biopsied blastocysts) with normal karyotypes undergoing preimplantation genetic testing for monogenic disease (PGT-M) due to monogenic disorders, matched for female age during the same period, were selected. Differences in euploidy rates and pregnancy outcomes after PGT-SR were compared among different types of structural rearrangement carriers. Furthermore, factors such as carrier sex, female age, and chromosomal breakpoint location were analyzed on the influence of embryonic euploidy. Results: (1) No statistically significant differences were observed among the RecT, RobT, and inversion groups in terms of male age, female body mass index, smoking history of both partners, basal follicle stimulating hormone, antral follicle count, number of oocytes retrieved, mature oocytes, 2 pronucleus zygotes, blastocyst formation, or biopsiable blastocysts (all P>0.05). (2) Significant differences were found among the RecT, RobT, and inversion groups in euploidy rate, mosaic embryo rate, aneuploidy rate, and the rates of derivative, de novo, and mixed aneuploidies (all P<0.05). The RecT group had the lowest euploidy rate, while the inversion group had the highest. The mosaic embryo rate was relatively higher in the inversion group. No significant difference was observed in the rate of aneuploidies unrelated to parental structural rearrangements among the RecT, RobT, and inversion groups (P>0.05). (3) Subgroup analysis within the RobT group showed that when the male had normal chromosomes and the female was the carrier, the embryonic aneuploidy rate was significantly higher than when the female was normal and the male was the carrier (52.34% vs 39.66%; P<0.01). In the RecT and inversion groups, breakpoint location was not an independent risk factor for embryonic aneuploidy (P>0.05). (4) Multivariate analysis using generalized estimating equation logistic regression showed that the likelihood of obtaining a euploid blastocyst were significantly lower in the RecT and RobT groups compared to the PGT-M control group (aOR=0.278, 95%CI: 0.237-0.327, P<0.01; aOR=0.569, 95%CI: 0.467-0.693, P<0.01, respectively), whereas the inversion group was similar to the control group (aOR=1.080, 95%CI: 0.802-1.455; P=0.613). Compared with the RecT group, the likelihood of aneuploidies unrelated to parental structural rearrangements was similar in the RobT and inversion groups (aOR=0.914, 95%CI: 0.739-1.131, P=0.408; aOR=0.792, 95%CI: 0.578-1.085, P=0.146, respectively). (5) In euploid single blastocyst frozen embryo transfer cycles, no statistically significant differences were found among the RecT, RobT, and inversion groups in endometrial preparation protocol, endometrial thickness on transfer day, human chorionic gonadotropin positivity rate, clinical pregnancy rate, spontaneous miscarriage rate, ongoing pregnancy rate, or ectopic pregnancy rate (all P>0.05). Conclusions: The type of chromosomal structural rearrangement significantly affects the embryonic euploidy rate. Chromosomal structural rearrangements primarily affect the segregation of rearrangement-related chromosomes, with no significant impact on the ploidy status of unrelated chromosomes. Factors such as the sex of the rearrangement carrier and female age influence embryonic euploidy, with heterogeneity observed among different rearrangement types. No significant statistical differences in pregnancy outcomes are found after transplantation of euploid embryos selected by PGT-SR.