Does Progesterone Predict a Successful Pregnancy for Both Young and Older Age Women in Fresh IVF/ICSI Transfer Cycles?

Introduction:Meta-analyses have shown that progesterone elevation is associated with a decreased probability of achieving pregnancy in fresh in vitro fertilisation (IVF) cycles. However, studies on the effect of maternal age on this association are scarce. Aims: To evaluate whether the serum progesterone (P) level on the day of trigger is useful for predicting successful pregnancy for women of all ages. Methods: This retrospective study comprised 1,517 fresh embryo transfer cycles performed in 1,258 women undergoing controlled ovarian stimulation between 2015 and 2021. We assessed the association of P levels and live birth across different maternal age groups. Results: Elevated P, with a cut-off of 0.8 ng/mL, was associated with a reduction in the live birth rate among women aged [Formula: see text]38 years (34.7% vs. 26.8%, [Formula: see text]), but not among women aged >38 years (10.5% vs. 10.5%). According to the multivariate generalised estimating equation (GEE) model, P level (odds ratio [OR] 0.447; 95% confidence interval [CI] 0.297-0.674; [Formula: see text]), embryo quality (OR 2.021; 95% CI 1.499–2.727; [Formula: see text]), luteinising hormone (LH) level (OR 0.930; 95% CI 0.869–0.996; [Formula: see text]) and maternal age (OR 0.919; 95% CI 0.873–0.969; [Formula: see text]) were significantly associated with live birth in the young group (aged [Formula: see text]38 years). Only maternal age was a significant negative predictor of live birth in the older group (aged >38 years). Conclusions: An elevated P level was more strongly associated with a reduced live birth outcome in young women (aged [Formula: see text]38 years) than in older women (aged >38 years).