Flexible progestin-primed ovarian stimulation is a safe and effective alternative to GnRH antagonist protocol in...

To test the hypothesis that flexible progestin-primed ovarian stimulation (fPPOS) is non-inferior to the gonadotropin-releasing hormone (GnRH) antagonist protocol in terms of safety and efficacy for patients undergoing controlled ovarian hyperstimulation and preimplantation genetic testing for aneuploidy (PGT-A).

This retrospective analysis included data from 548 cycles involving 367 women aged 35 to 45 years. The fPPOS and GnRH antagonist groups comprised 307 cycles (56%) and 241 cycles (44%), respectively. All participants underwent absolute blastocyst culture, trophectoderm biopsy, and PGT-A, with advanced maternal age as the sole indication. The primary outcomes were incidence of premature luteinizing hormone (LH) rise (>10 mIU/mL), cycle cancellation due to premature ovulation, and euploid blastocyst rate per injected metaphase II oocyte. Spearman's rho correlation and the generalized linear model (logit) were applied for statistical analysis.

The incidence of premature LH rise (8.2% versus 6.6%; p=0.302) and cycle cancellation due to premature ovulation (2% versus 0.4%; p=0.112) did not differ significantly between the fPPOS and GnRH antagonist groups. Maturation, fertilization, and blastulation rates were also similar (p>0.05). The euploid blastocyst rates per biopsy (50.12% versus 53.06%; p=0.317) and per injected metaphase II oocyte (23.84% versus 23.34%; p=0.231) were comparable between groups. Secondary outcomes, including rates of positive pregnancy tests, implantation, ongoing pregnancy, biochemical pregnancy losses, and early miscarriages, were also similar (p>0.05).

The fPPOS protocol represents a viable alternative to the GnRH antagonist protocol for patients aged 35 years or older undergoing PGT-A.