Objective: This retrospective analysis of combined data (one Phase II and three Phase III clinical trials) of patients with oligo- or anovulatory infertility aimed to evaluate the association between pregnancy and midluteal serum progesterone (P4) level following ovulation induction and hence the indicative value of P4 for ovulation and pregnancy achievement.
Study design: All patients (n = 913) were treated with human follicle-stimulating hormone. Cycles (n = 1,554) with one or two serum P4 levels in the luteal phase (days 5-12) following human chorionic gonadotropin administration and complete data on cycle outcome were included.
Results: Clinical pregnancy was achieved in 295/1,554 (19.0%) cycles; 87.5% of these led to live births (16.6%/cycle). Including and excluding multiple pregnancy data, 88% and 86% of all live births had P4 values >10 ng/mL, respectively. Overall clinical pregnancy rate plateaued at midluteal P4 levels >25 ng/mL but, when multiple pregnancies were excluded, plateaued at 20-25 ng/mL and then decreased. Mean midluteal P4 levels were twice as high in multiple versus singleton pregnancies.
Conclusion: A midluteal P4 level >10 ng/mL may represent an appropriate threshold for indication of ovulation resulting in live birth. Multiple pregnancies were associated with higher mean midluteal P4 levels.