Polycystic ovary syndrome increases the rate of early spontaneous miscarriage in women who have undergone single vitrified euploid blastocyst transfer.

RESEARCH QUESTION: Does polycystic ovary syndrome (PCOS) independently influence the risk of early spontaneous miscarriage in patients undergoing single euploid vitrified blastocyst transfer? DESIGN: This observational cohort study retrospectively analysed 1498 patients undergoing their first single euploid blastocyst frozen transfer cycles between October 2016 and December 2021. Patients were divided into PCOS and non-PCOS groups according to the Rotterdam criteria. Logistic regression analysis was conducted to study the independent effect of maternal PCOS status on early spontaneous miscarriage after single euploid embryo transfer after adjusting for confounding factors. RESULTS: No statistically significant differences were identified in the rates of positive pregnancy test (68.95% versus 64.86%, P = 0.196) or clinical pregnancy (59.93% versus 57.33%, P = 0.429) between the PCOS and non-PCOS groups after single euploid embryo transfer. Early spontaneous miscarriage occurred more frequently in women with PCOS compared with controls (18.67% versus 12.00%, P = 0.023). In single euploid embryo transfer cycles, PCOS significantly increased the incidence of early spontaneous miscarriage after adjusting for some potential confounders (adjusted odds ratio 1.649, 95% CI 1.032 to 2.635, P = 0.036). CONCLUSIONS: Although no significant difference was observed in clinical pregnancy rates, PCOS status increased the risk of early spontaneous miscarriage after single vitrified euploid blastocyst transfer, suggesting an additional role of endometrial dysfunction affected by endocrine disorders. Further studies are needed to investigate the specific mechanisms and effective intervention strategies.