Endometrial Preparation for Frozen–Thawed Embryo Transfer With or Without Pretreatment With GnRH Agonist: A Randomized Controlled Trial at Two Centers

Abstract

Objective This prospective randomized controlled trial compared the reproductive outcomes of frozen embryo transfer (FET) with hormone replacement treatment (HRT) with or without gonadotropin-releasing hormone agonist (GnRHa) pretreatment. Methods A total of 133 patients scheduled for HRT-FET mainly because of tubal and/or male factors who received two high-quality cleavage-stage embryos were enrolled at two participating centers. The GnRHa group ( n = 65) received GnRHa pretreatment, while the control group ( n = 68) did not. Analysis was based on the intention-to-treat (ITT) principle. Results Among the 133 participants, 130 (97.7%) underwent embryo transfer and 127 (95.5%) completed the protocol. The clinical pregnancy rate according to ITT did not differ between the GnRHa and control groups [39/65 (60.0%) vs . 41/68 (60.3%), p = 0.887]. The implantation rate (47.6% vs . 45.3%, p = 0.713), early pregnancy loss rate (5.1% vs . 19.5%, p = 0.09), and live birth rate (49.2% vs . 50.0%, p = 0.920) were also comparable between groups. Conclusion Pretreatment with GnRHa does not improve the reproductive outcomes for women receiving HRT-FET. Clinical Trial Registration The study was registered with the Chinese Clinical Trial Registry (ChiCTR-IOR-17014170; http://www.chictr.org.cn ).