Comparison between GnRH agonist and antagonist protocols for severe endometriosis in assisted reproductive cycles

Purpose: Endometriosis may influence different aspects of reproductive physiology including folliculogenesis, ovulation, embryo quality, and fertilization. Recent data demonstrate that patients with endometriosis-associated infertility undergoing in vitro fertilization (IVF) have a reduction of pregnancy rates compared to women with other indications for IVF. The aim of the study is to evaluate the outcomes of IVF after controlled ovarian hyperstimulation (COH) with GnRH antagonist (GnRH-ant) or GnRH agonist (GnRH-a) in severe endometriosis patients. Methods: A total of 101 patients with severe endometriosis undergoing IVF cycles were retrospectively enrolled into two groups in relation to hypothalamic inhibition before COH, obtained respectively with leuprorelin and cetrorelix. We evaluated characteristics of COH and clinical outcomes (overall pregnancy rate, implantation rate, spontaneous miscarriages, ectopic pregnancies, and clinical pregnancy rates). Results: The group treated with GnRH-ant presented a similar number of MII oocytes and good quality embryos while using a lower amount of gonadotropins. Outcomes of COH with both GnRH-ant and GnRH-a were similar in patients with stage III-IV endometriosis. The number of retrieved oocytes, the number of obtained embryos, the implantation rates, and the clinical pregnancy rates were similar with GnRH-ant and GnRH-a protocols. Conclusions: Considering the pregnancy outcomes, COH with both GnRH-ant and GnRH-a protocols do not present statistical differences in patients with severe endometriosis, but the GnRH-ant protocol could be more convenient in term of gonadotropins amount and patient discomfort.