Prolonged oral GnRH-antagonist administration before euploid embryo transfer in patients with endometriosis: a prospective randomized pilot non-inferiority trial

RESEARCH QUESTION: Is oral administration of a gonadotrophin releasing hormone (GnRH) antagonist for 2 months before euploid embryo transfer in patients with endometriosis non-inferior to intramuscular administration of a long-acting GnRH agonist for a similar period? DESIGN: Prospective randomized non-inferiority pilot trial of infertility patients with surgically diagnosed endometriosis. Thirty patients were randomized to receive either oral elagolix 200 mg twice daily for 56 days (group 1; n = 15) or an intramuscular depot preparation of leuprolide acetate 3.75 every 28 days (group 2; n = 15) before euploid embryo transfer. RESULTS: No differences were found in baseline characteristics between the two groups. Nor were any differences found between the two groups in maximal endometrial thickness before embryo transfer (10.9 ± 2.8 mm versus 10.3 ± 2.0 mm; P = 0.54). Despite a trend towards transfer of a higher percentage of day-5 euploid blastocysts in group 2 (53% versus 80%), no differences were found in positive pregnancy tests (86.7% versus 93.3%; P = 0.54) or live birth rates between the groups (87% versus 80%; P = 0.62). CONCLUSION: Administration of the oral GnRH antagonist elagolix in appropriate doses for 2 months in women with endometriosis before euploid embryo transfer yields highly encouraging outcomes that are equivalent to those achieved with parenteral administration of a GnRH agonist, which could make this a more desired approach in these patients.