Clinical outcomes of personalized frozen-thawed embryo transfer timing for patients with recurrent implantation failure

BACKGROUND: Recurrent implantation failure (RIF) is a critical problem for assisted reproduction technology. High-quality embryos and the synchronization endometrium both have great significance. How to get the optimal endometrial receptivity is a challenge for implantation and pregnancy of infertile patients with RIF. The objective of this study is to investigate personalized protocol of frozen-thawed embryo transfer (FET) cycles, and its effect on clinical outcomes in patients with RIF. METHODS: We chose 91 RIF patients from January 2017 to June 2019 in the Reproductive Medicine Center of the First Hospital of Lanzhou University. A total of 100 FET cycles were undertaken with a gonadotropin-releasing hormone agonist (GnRH-agonist) protocol combined with hormone replacement therapy (HRT) for endometrial preparation. The patients were divided into two groups: the routine group (cleavage embryo transferred at day 3 after luteal support) included 48 cycles; the personalized group included 52 cycles with delayed endometrial trigger and luteal support (the time of embryo transfer depended on the level of serum hormone and endometrial thickness). RESULTS: The data showed the personalized group had longer time for endometrial preparation. On the day of embryo transfer, serum progesterone (P) and the E(2)/P ratio was significantly different compared with the routine group (P<0.05). The clinical pregnancy rate in the routine group was 35.42% (17/48) and 59.62% (31/52) in the personalized group (P<0.05). The abortion rate was not significantly different. CONCLUSIONS: For women with RIF, personalized timing for transfer of FET resulted in a higher clinical pregnancy rate compared with routine protocol.