Abstract: Objective：To investigate the effects of different GnRHa down-regulation protocols on the clinical outcomes of frozen-thawed embryo transfer (FET) in infertile women with endometriosis (EMs). Methods：A total of 320 FET cycles of EMs infertile patients were collected in our hospital from January 2016 to January 2018. The patients were randomly grouped into two groups: 160 cases in the group A were treated with the artificial cycle combined with GnRHa down-regulation，and 160 cases in the group B were treated with artificial cycle. Demographic data, cycle characteristics and clinical outcome were compared between the two groups. Results：There were no significant differences in demographic data, serum CA125 level, progesterone level, the number of embryos transferred and miscarriage rate between the two groups (P＜0.05). Compared with the Group B, the Group A had significantly lower estradiol level (P＜0.05), and higher endometrium thickness, proportion of type A endometrium, clinical pregnancy rate, implantation rate and live birth rate (all P＜0.05). Conclusions: The artificial cycle combined with GnRHa down-regulation protocols is helpful to improve the clinical outcome of FET in those infertile women with EMs.

Key words: Endometriosis, Fertilization in vitro, Embryo transfer, Gonadotropin-releasing hormone, Pregnancy outcome