Effect of cervical incompetence in patients with polycystic ovary syndrome enduring second- trimester abortion during the frozen-embryo transfer cycle: A retrospective study

Abstract

Abstract Background Second-trimester abortion is a critical issue in infertile women with polycystic ovary syndrome (PCOS) treated with the assisted reproductive technology (ART). Cervical incompetence (CI) is suspected to play a key role in the second-trimester abortions. We aimed to investigate the association between CI and second-trimester abortion in women with PCOS, especially during the frozen-embryo transfer cycle. Methods This retrospective cohort study included patients who underwent frozen-thawed embryo transfer and experienced second-trimester abortion between January 2012 to January 2020. Logit-transformed propensity score matching (PSM) was used to assess covariates. The primary objective was to examine the impact of CI on the occurrence of mid-pregnancy abortion in a population undergoing frozen-embryo transfer, and to identify the factors associated with it during the gestational period ranging from 13 weeks 0 days to 27 weeks 6 days. Patients were classified into PCOS and non-PCOS groups, and CI and non-CI subgroup analyses were conducted. Results Overall, 278 patients were included: 139 each in the PCOS group and the non-PCOS groups. In the PCOS group, a greater proportion of miscarriages were attributed to CI compared to the control group (P = 0.019). Subsequently, CI and non-CI subgroup analyses were performed, revealing a higher incidence of transfer cleavage-stage embryos in the CI group than in the blastocysts group (P = 0.001). Moreover, the miscarriage-related gestational age varied significantly between the two groups (CI group: 22 weeks; control group: 20 weeks; P = 0.039). The results showed no statistically significant differences in the three different endometrial preparation protocols, endometrial thickness, basal serum testosterone level, the number of embryos transferred, and the interval between oocyte retrieval and thawing. Binary logistic regression analysis revealed that cleavage embryo transfer (95% confidence interval: 1.009–4.206, P: 0.047) was associated with increased risk of CI in the PCOS group. Conclusions CI independently predicted a higher risk of second-trimester abortion in patients with PCOS during the frozen-embryo transfer cycle. Blastocyst transfer may be beneficial for these individuals, and further research should explore the potential use of prophylactic cervical cerclage or drug therapy to improve pregnancy outcomes in women with PCOS.