Abstract
OBJECTIVE: To compare the effectiveness of medroxyprogesterone acetate (MPA) vs. cetrorelix (GnRH antagonist) in preventing premature LH surge during ovarian stimulation in assisted reproductive technology (ART) cycles, including cycles for intracytoplasmic sperm injection (ICSI) and fertility preservation. DESIGN: Single-center, retrospective observational cohort study. SETTING: Private fertility clinic in Santiago, Chile. PATIENTS: A total of 2,964 ART cycles conducted between January 2018 and December 2022 were included after excluding 425 cycles that were cancelled. Among these, 1,793 were ICSI cycles (1,529 antagonist, 264 MPA) and 1,171 were fertility preservation cycles (862 antagonist, 309 MPA). INTERVENTIONS: Ovarian stimulation using recombinant FSH and/or menotropins with ovulatory suppression by either oral MPA (10 mg/day) or daily cetrorelix (0.25 mg). MAIN OUTCOME: Follicular response, oocyte yield, embryo development, euploidy and mosaicism rates, implantation, clinical pregnancy, miscarriage, and live birth outcomes. RESULTS: In fertility preservation cycles, MPA produced higher numbers of follicles ≥17 mm (8.7 vs. 6.7), oocytes retrieved (12.2 vs. 10.7), and mature oocytes (9.1 vs. 7.9; p < 0.01 for all). In ICSI PGT-A cycles, MPA was associated with a higher number of biopsied blastocysts and frozen embryos per patient, while euploid, implantation, and live birth rates were comparable to the antagonist group. Cancellation, fertilization, and miscarriage rates did not differ significantly. CONCLUSIONS: MPA is a safe and effective oral alternative to GnRH antagonists for LH suppression during ovarian stimulation in ART, providing comparable reproductive outcomes while reducing treatment burden.