Comparison of the cumulative live birth rates after 1 in vitro fertilization cycle in women using gonadotropin-releasing hormone antagonist protocol vs. progestin-primed ovarian stimulation: a propensity score-matched study.

Objective: To determine whether gonadotropin-releasing hormone (GnRH) antagonist protocol can improve cumulative live birth rates (CLBRs) and shorten the time to live birth (TTLB) in unselected patients compared with progestin-primed ovarian stimulation (PPOS).

Design: A propensity score-matched retrospective cohort study design.

Setting: Tertiary-care academic medical center.

Patient(s): A total of 6,520 women with infertility aged 20-50 years were included.

Intervention(s): Patients underwent either the GnRH antagonist protocol (n = 5,004) or PPOS (n = 1,516) on the basis of the assessment of the attending physicians. One-to-one propensity score matching was performed with a caliper of 0.02. Women who were not matched were excluded from the analyses.

Main Outcome Measure(s): The CLBR of which the ongoing status had to be achieved within 22 months from the day of ovarian stimulation and TTLB.

Result(s): Each group comprised 1,424 couples after propensity score matching, and the baseline demographic characteristics of the couples after matching were comparable between the 2 groups. The cycle cancellation rate was significantly lower in the GnRH antagonist group than in the PPOS group (12.9% vs. 19.6%). The implantation rate, clinical pregnancy rate, ongoing pregnancy rate, and live birth rate per transfer were comparable between the 2 groups. However, CLBRs after 1 complete IVF cycle were significantly higher in the GnRH antagonist group than in the PPOS group (36.0% vs. 32.2%; Risk ratio = 1.12; 95% confidence interval [CI], 1.01-1.24). The average TTLB was significantly shorter in the GnRH antagonist group than in the PPOS group (9.3 months vs. 12.4 months). Using the Kaplan-Meier analysis, the cumulative incidence of ongoing pregnancy leading to live birth was significantly higher in the GnRH antagonist group than in the PPOS group (85.1% vs. 66.1%, Log-rank test). A Cox proportional hazard model revealed that women who underwent the antagonist protocol were 2.32 times more likely to achieve a live birth than those who used PPOS (hazard ratio [HR] = 2.32; 95% CI, 1.91-2.83). Subgroup analysis revealed that women who used the antagonist protocol were more likely to achieve a live birth than women who used PPOS across the 3 antral follicle count (AFC) strata (AFC ≤ 5, AFC 6-15, and AFC > 15), 2 age strata (<35 and ≥35 years), and first cycle or repeated cycle. The difference was greatest among women whose AFC was ≤5 and who were aged ≥35 years, effectively becoming smaller in the group with high ovarian reserve and younger age.

Conclusion(s): In unselected women undergoing IVF, the GnRH antagonist protocol was associated with a higher CLBR and a shorter TTLB compared with PPOS.