Clinical outcomes following GnRH antagonist protocol change to PPOS protocol versus GnRH antagonist protocol in patients with pre-elevated progesterone: a propensity score matching study

To investigate the impact of changing to the PPOS protocol in the population with a premature progesterone increase (≥ 0.9 ng/mL) from the antagonist protocol on the clinical outcomes. The study was a retrospective cohort, propensity score-matched study on the clinical outcomes of patients changing from antagonist protocol to the PPOS protocol with a premature progesterone increase compared to patients consisted with the antagonist protocal. A total of 188 pairs (376 samples) were successfully matched through PSM matching (tolerance: 0.001) from January 2020 to December 2024. After adjusted by Generalized linear models, the number of retrieved oocytes in the antagonist-to-PPOS protocol is slightly lower (12.80 [12.29–13.13] vs. 13.59 [13.06–14.13], P = 0.03), the 2PN fertilized eggs, and available embryos were comparable between the antagonist-to-PPOS group and the antagonist group. The number of blastocysts (4.52 [4.18–4.89] vs. 3.73 [3.39–4.10], P = 0.002), the number of high-quality blastocysts per person(3.28 [2.98–3.63] vs. 2.45 [2.16–2.79], P<0.001), and the high-quality blastocysts rate (32.15 [28.36–35.94]% vs. 26.25 [22.44–30.05]%, P = 0.03) were higher in the antagonist-to-PPOS group. The clinical pregnancy rate in the first FET cycle, and in the completed FET cycles were comparable between the antagonist group and the antagonist-to-PPOS protocol groups. Through logistic regression analysis, the transition from the antagonist protocol to the PPOS protocol had no adverse influence on the clinical pregnancy rate. Switching from the antagonist protocol to the PPOS protocol in the population with elevated progesterone ≥ 0.9 ng/ml during the process of ovulation induction did not adversely affect clinical pregnancy rates, while showing improved blastocyst quality metrics.