Comparison of stimulated cycles with low dose r-FSH versus hormone replacement cycles for endometrial preparation prior to frozen-thawed embryo transfer in young women with polycystic ovarian syndrome: A propensity scores matching analysis from 1434 patients

Abstract Objective The principal purpose of this study was to compare reproductive outcomes for stimulated cycles (STC) and hormone replacement cycles (HRC) for endometrial preparation before frozen-thawed embryo transfer (FET) in young women with polycystic ovary syndrome (PCOS). Methods We conducted a retrospective study of 1434 FET cycles from January, 2017 to March, 2020 in our reproductive center, in which stimulated and hormone replacement cycles were used for endometrial preparation. Pregnancy outcomes of couples undergoing routine STC-FET or HRC-FET were analyzed before and after propensity score matching (PSM). Results Data on 1234 HRC protocols (86% of the total) and 200 STC protocols (14%) were collected. After PSM, 199 patients were included in both groups, respectively. There was no significant difference in positive pregnancy rate (52.7% vs. 54.8%, p = 0.763), clinical pregnancy rate (51.8% vs. 52.8%, p = 0.841), live birth rate (45.2% vs. 43.7%, p = 0.762), pregnancy loss rate (9.7% vs. 16.2%, p = 0.164) and ectopic pregnancy rate (1.5% vs. 0.5%, p = 0.615) between STC protocols and HRC protocols. Conclusion STC for endometrial preparation had similar pregnancy outcomes compared with HRC protocols by excluding heterogeneous factors after PSM. Evidence is available which shows that for young women with PCOS who were undergoing in-vitro fertilization, HRC could be a reasonable choice for patients who are unwilling to accept injections. Additionally, STC may offer more flexibility for young PCOS patients and reproductive centres.