Controlled ovarian stimulation for endometriosis patients with ultra‐long GnRH‐agonist or GnRH‐antagonist protocols: A retrospective study by propensity score matching

Although in vitro fertilization with embryo transfer is the most effective treatment for infertile patients with endometriosis, ovarian stimulation protocols are controversial.We recruited 639 patients with endometriosis from January 2016 to June 2020; 111 and 528 patients were treated with the gonadotropin-releasing hormone (GnRH) antagonist and ultra-long GnRH agonist protocols, respectively. Potential baseline differences between the regimens were adjusted by propensity score matching. Clinical and laboratory data, including the cumulative clinical pregnancy rate (CCPR) and cumulative live birth rate (CLBR), were compared.Ovulation induction required significantly longer use of gonadotropins in the GnRH agonist group. However, the GnRH agonist group had a lower starting dose of gonadotropin (all p < 0.05). Furthermore, significantly lower clinical pregnancy, implantation, and live birth rates were observed in the GnRH antagonist group receiving fresh assisted reproductive technology cycles (all p < 0.05); however, pregnancy outcomes using the subsequent freeze-thaw cycles for the same oocyte retrieval were not significantly different. CCPR and CLBR for the oocyte retrieval cycles of the antagonist and ultra-long agonist protocols were similar. The ultra-long agonist protocol resulted in more favorable implantation of fresh embryos and improved clinical outcomes of the fresh cycle.This novel strategy could be appropriate for endometriosis patients who are temporarily unsuitable for fresh embryo transfer. The GnRH antagonist protocol can be combined with the whole embryo freezing strategy to achieve CCPR and CLBR similar to the ultra-long agonist regimen, thus simultaneously avoiding the long pre-treatment duration of GnRH agonists during the ultra-long agonist protocol.