Effect of human chorionic gonadotropin on pregnancy outcomes in patients with polycystic ovary syndrome undergoing frozen-thaw embryo transfer in hormone replacement therapy cycles: A retrospective cohort study

Abstract

Abstract Background Endometrial preparation protocols for frozen-thawed embryo transfer (FET) and hormone replacement therapy (HRT) lack luteinizing hormone (LH) peaks and luteal function due to anovulation. Human chorionic gonadotropin (hCG) supplementation improves endometrial receptivity and promotes embryo implantation. Therefore, we aimed to compare whether there was a difference in pregnancy outcomes with hCG supplementation prior to secretory transformation in patients with polycystic ovary syndrome (PCOS). Methods Patients undergoing their first FET cycle between 2018 and 2022 at the university-affiliated reproductive and genetic centre participated in this retrospective cohort study. After standard screening and propensity score matching, patients were assigned to the HRT (n = 343) and HRT + hCG groups (n = 195). The primary outcomes were implantation rate (IR) and live birth rate (LBR), and the secondary outcomes included other pregnancy-related issues. Results There were no significant differences in IR or LBR between the two groups. However, compared to the HRT group, the HRT + hCG group had a significantly higher biochemical pregnancy rate (BPR) (75.9% vs. 64.7%, P = 0.007); the clinical pregnancy rate was also higher, but the difference was not significant (58.5% vs. 50.4%, P = 0.073). Ectopic pregnancy, ongoing pregnancy, miscarriage, and preterm birth rates were similar in both groups. After adjusting for possible confounders, logistic regression analyses showed that the effect of hCG addition on BPR (OR 0.585, 95% CI 0.393–0.872, P = 0.009) remained significant. Subsequent subgroup analyses showed a statistically significant improvement in BPR after hCG supplementation in cleavage-stage embryo transfer cycles (75.3% vs. 64.7%, P = 0.020). Conclusions In patients with PCOS, intramuscular hCG injection before secretory transformation had no impact on pregnancy outcomes, except for BPR. Notably, the addition of hCG did not show a significant trend towards the increased BPR observed in patients undergoing blastocyst transfer. Future prospective randomised controlled studies are required to confirm our findings.