Title: Does progesterone as predictive for a successful pregnancy along all age groups in fresh IVF/ICSI transfer cycles?

Abstract

Abstract Background Meta-analyses have shown that progesterone (P) elevation is associated with a decreased probability of pregnancy achievement in fresh in vitro fertilization (IVF) cycles. The objective of this study is to evaluate the P level, the P to oocyte ratio (P/O) and the P to follicle (> 14 mm) ratio (P/F) in prediction of successful pregnancy in different age groups. Methods This was a retrospective, single-centre cohort study with 1517 cycles performed in 1305 patients undergoing controlled ovarian stimulation and fresh embryo transfer cycles between 2015 and 2021. We investigated the association of serum progesterone level on the day of ovulation trigger with live birth among patients age ≤ 35 (group 1), 36–39 (group 2) and ≥ 40 (group 3). Results The progesterone level was significantly associated with the live birth rate in group 1 (aOR 0.422, 95% CI 0.231–0.770, p = 0.005), but not in group 2 (aOR 0.626, 95% CI 0.362–1.084, p = 0.095) and group 3 (aOR 0.311, 95% CI 0.042–2.284, p = 0.251). The live birth rate was significantly reduced in group 1 with P > 1.00 ng/mL (36.8% vs. 23.6%, p = 0.002). No significant difference in the live birth rate was found with P > 1.00 ng/mL in both groups 2 and 3. Both the P/O and P/F ratios, though were more predictive than P alone in live birth rate among all age groups, the values increased substantially with age. Conclusions Our results suggest that progesterone elevation is less predictive to live birth rate among patients age above 35. While the P/O or P/F ratio are significantly higher among women without live birth in all 3 age groups, their age-dependent values suggest the definition of a universal threshold should be warranted.