Effect of human chorionic gonadotropin injection before frozen-thawed embryo transfer: A retrospective cohort study

The aim of this study is to investigate the effect of human chorionic gonadotropin (hCG) in hormone replacement regimen for frozen-thawed embryos. We performed a retrospective cohort study and included patients who underwent frozen embryo transfer (FET) between January 1, 2020 and May 31, 2022. According to the protocols for the FET cycle, the patients were divided into control (n = 238) and hCG groups (n = 216). The clinical pregnancy rate, live birth rate, early abortion rate, late abortion rate, and ectopic pregnancy rate were compared between the 2 groups. There was a significant difference in clinical pregnancy rate between the hCG and control groups (55.1% vs 45.8%, P = .048). The ectopic pregnancy rate decreased (5.0% vs 6.4%, P = .654), while the live birth rate increased (36.1% vs 29.0%, P = .105) in the hCG group. However, these differences were not statistically significant. The administration of hCG injection in HRT-FET cycles alone was also found to be associated with clinical pregnancy by logistic regressive analysis. HCG injection in the hormone replacement regimen for FET increased the clinical pregnancy rate.