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 Single-Center Retrospective Cohort Study from China

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 by propensity score matching (PSM) and multivariable logistic regression analyses. 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 and HRC protocols. Subsequent multivariate logistic regression analysis also yielded similar results. CONCLUSION: STC for endometrial preparation had similar pregnancy outcomes compared with HRC protocols. Evidence is available which shows that for young women with PCOS in preparation for FET, HRC could be a reasonable choice for patients who are unwilling to accept injections. However, STC may reduce unnecessary anxiety and operational costs and offer more flexibility for patients. Eventually, we must embrace the concepts of individualization, securitization, and optimization in the clinic.