Comparison of a novel flexible progestin primed ovarian stimulation protocol and the flexible gonadotropin-releasing hormone antagonist protocol for assisted reproductive technology

Objective: To determine whether a flexible progestin primed ovarian stimulation (fPPOS) protocol is effective for preventing premature ovulation. Design: Retrospective cohort study. Setting: Private assisted reproduction center. Patient(s): Eighty-seven oocyte donors and 191 recipients of fresh oocytes. Intervention(s): Each donor was stimulated with a flexible gonadotropin-releasing hormone (GnRH) antagonist protocol in one cycle and with the new fPPOS protocol in the other, within a period of 6 months. FSH was started on cycle day 2-3, and 0.25 mg/day GnRH antagonist or 10 mg/day medroxyprogesterone acetate (MPA) was started on stimulation day 7 or when the leading follicle reached 14 mm, whichever came first. Main Outcome Measure(s): Duration of stimulation, gonadotropin consumption, duration of GnRH antagonist or MPA administration, number of metaphase II oocytes, and pregnancy rates in fresh oocyte recipients. Results: Duration of stimulation was 11 (10-11) days in both groups. Total gonadotropin consumption was similar. Pituitary suppression was started on day 7 and lasted for 5 days in each group. There were no premature ovulations in any group. The fPPOS yielded a significantly higher number of cumulus oocyte complexes than GnRH antagonist cycles (33 [21-39] vs. 26 [18-36], respectively). Likewise, the fPPOS generated significantly more metaphase II oocytes than GnRH antagonist cycles (24 [17-34] vs. 21 [15-28], respectively). Recipients of fresh oocytes from fPPOS and GnRH antagonist cycles had similar cleavage, blastulation, implantation, and live birth/ongoing pregnancy rates (50% vs. 48.6%). Conclusion(s): FPPOS with MPA seems to be an effective choice for preventing premature ovulation in women undergoing ovarian stimulation without compromising oocyte quality. ((C) 2019 by American Society for Reproductive Medicine.)