Clinical outcomes in oocyte donation cycles: GnRH-antagonists versus progesterone-primed ovarian stimulation with...

In oocyte donation cycles, does the use of oral natural micronized progesterone (NMP) result in comparable clinical outcomes, compared with gonadotrophin releasing hormone (GnRH) antagonist treatment?

Retrospective analysis of 1368 oocyte donation cycles (January 2018 to December 2022), and laboratory (n = 793) and clinical outcomes (n = 645) in matched recipients. Donors initiated ovarian stimulation in early follicular phase. To prevent a premature LH peak, the study group received natural micronized progesterone orally concurrently with FSH administration, whereas the control group began GnRH antagonist treatment in a flexible protocol. Live birth rate was the primary outcome.

Duration of stimulation and total gonadotrophins dose were comparable between groups. The NMP group yielded significantly higher retrieved oocytes (15.9 ± 8.5 versus 13.1 ± 7.9; P < 0.001) and mature oocytes (12.8 ± 7.3 versus 11.7 ± 7.3; P = 0.003), and a lower maturation rate (80.89 ± 16.78% versus 89.49 ± 14.48%; P < 0.001). These donors had higher fertilization rates (81.3% versus 74.3%; P < 0.001) and number of usable embryos (4.6 ± 2.0 versus 4.1 ± 2.0; P < 0.001) compared with those treated with a GnRH antagonist. In matched recipients undergoing fresh embryo transfer, reproductive outcomes, including live birth rates, were similar in the GnRH antagonist and NMP groups (47.2% and 44.6%).

Comparable live birth rates were found in fresh embryo transfers for recipients across both groups. The NMP protocol was associated with a higher number of mature oocytes but lower oocyte maturation rate, higher fertilization rates and number of usable blastocysts. Progesterone priming may positively influence oocyte donation cycles.