A retrospective comparison of live birth rate in freeze-all cycles between progestin-primed ovarian stimulation with dydrogesterone and GnRH antagonist protocols.

RESEARCH QUESTION: Does progestin-primed ovarian stimulation (PPOS) using dydrogesterone yield a live birth rate comparable with the gonadotrophin-releasing hormone (GnRH) antagonist protocol in in-vitro fertilization (IVF) freeze-all cycles?

DESIGN

This retrospective cohort study, conducted at a tertiary hospital from June 2022 to January 2024, included 1045 women aged 18-40 years undergoing IVF/intracytoplasmic sperm injection with freeze-all indications. Participants were assigned to receive PPOS-dydrogesterone (n = 482) or GnRH antagonist (n = 563), followed by frozen embryo transfer (FET). The primary outcome was the live birth rate after the first FET cycle.

RESULTS

The live birth rate after the first FET cycle were comparable between the PPOS-dydrogesterone (35.1 %) and GnRH antagonist (40.3 %) groups (p = 0.092), showing no significant difference. The PPOS-dydrogesterone group experienced a longer stimulation period [mean ± standard deviation (SD) 8.4 ± 2.0 vs 8.0 ± 2.0 days; p = 0.002] and a higher gonadotrophin dosage (mean ± SD 2622.2 ± 818.8 vs 2413.4 ± 663.4 IU; p < 0.001) than the GnRH antagonist group, but produced more blastocysts (mean ± SD 6.3 ± 3.9 vs 5.6 ± 3.5; p = 0.013). Multivariate analysis showed that age [adjusted odds ratio (aOR) 0.96, 95 % confidence interval (CI) 0.93-0.99; p = 0.006] and anti-Müllerian hormone concentration (aOR 1.05, 95 % CI 1.01-1.10; p = 0.011) were key predictors of live birth, overshadowing protocol effects (aOR 1.27, 95 % CI 0.98-1.67; p = 0.076).

CONCLUSION

The PPOS-dydrogesterone protocol has a similar live birth rate to the GnRH antagonist protocol in IVF freeze-all cycles, with added benefits in blastocyst yield despite higher stimulation demands. Patient factors, rather than protocol choice, primarily drive outcomes, positioning the PPOS-dydrogesterone protocol as an effective alternative to the GnRH antagonist protocol.