OB/GYN & Women's Health
COHORT
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MPA vs GnRH antagonist for LH surge prevention in ART shows higher oocyte yield in fertility preservation cycles
Frontiers in Medicine
Published April 1, 2026
DOI ↗
This retrospective observational cohort study compared two protocols for preventing premature luteinizing hormone (LH) surge during ovarian stimulation in assisted reproductive technology (ART) cycles. Conducted at a private fertility clinic in Santiago, Chile, it analyzed 2,964 ART cycles (after excluding 425 cancelled cycles), including 1,793 intracytoplasmic sperm injection (ICSI) cycles and 1,171 fertility preservation cycles. The intervention was ovarian stimulation using recombinant FSH and/or menotropins with ovulatory suppression by oral medroxyprogesterone acetate (MPA) at 10 mg/day, compared to the same stimulation protocol with daily cetrorelix (GnRH antagonist) at 0.25 mg.
In fertility preservation cycles, the MPA protocol was associated with higher follicular response and oocyte yield compared to the antagonist protocol. Specifically, MPA was linked to higher mean numbers of follicles ≥17 mm (8.7 vs 6.7), total oocytes retrieved (12.2 vs 10.7), and mature oocytes (9.1 vs 7.9). The study mentions p values were reported for these comparisons but does not provide the exact values. Results for ICSI cycles and other secondary outcomes (embryo development, euploidy, implantation, pregnancy, miscarriage, live birth) were not reported.
Safety and tolerability data were not reported. The study has several important limitations: it is retrospective and observational, meaning it can only show association, not causation. The single-center design in Chile may limit generalizability to other populations and settings. The analysis only partially reports results, focusing on fertility preservation cycles, leaving ICSI cycle outcomes unclear. Funding sources and potential conflicts of interest were not disclosed.
For clinical practice, these findings suggest oral MPA may be associated with a more favorable follicular response in fertility preservation cycles within this specific clinic context. However, the retrospective, observational nature and lack of reported primary outcome, safety data, and comprehensive results for all cycle types preclude definitive conclusions. Clinicians should interpret these results cautiously and await prospective, randomized controlled trials to confirm these observations and assess clinical pregnancy and live birth outcomes.
When a woman decides to freeze her eggs, every egg counts. A new look at past fertility treatments in Chile suggests that using an oral medication called medroxyprogesterone acetate (MPA) might help. In cycles where women were freezing eggs for the future, those using MPA had more large follicles, more eggs retrieved, and more mature eggs ready for freezing than those using the standard daily injection (a GnRH antagonist).
The study reviewed nearly 3,000 fertility treatment cycles. It specifically found that in egg-freezing cycles, the average number of mature eggs was 9.1 with the pill versus 7.9 with the injection. More eggs can mean more chances later, which is a big deal for someone investing in their future family.
It's crucial to understand what this study is—and isn't. This wasn't a controlled experiment; it was a look back at past patient records from a single clinic. We don't know if the women in the two groups were identical in other ways that could affect egg count. The study also didn't report on pregnancy or birth outcomes, so we can't say if more eggs led to more babies. No safety issues were reported, but the study wasn't designed to thoroughly compare side effects.
In short, this points to a potentially simpler, pill-based option that deserves a closer look in more rigorous research. For now, it's an interesting observation, not a proven new standard of care.
What this means for you: An oral pill was linked to more eggs retrieved in fertility preservation, but more research is needed.
View Original Abstract ↓
ObjectiveTo 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.DesignSingle-center, retrospective observational cohort study.SettingPrivate fertility clinic in Santiago, Chile.PatientsA 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).InterventionsOvarian stimulation using recombinant FSH and/or menotropins with ovulatory suppression by either oral MPA (10 mg/day) or daily cetrorelix (0.25 mg).Main outcomeFollicular response, oocyte yield, embryo development, euploidy and mosaicism rates, implantation, clinical pregnancy, miscarriage, and live birth outcomes.ResultsIn 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