Mid-Luteal 17-OH Progesterone Levels in 614 Women Undergoing IVF-Treatment and Fresh Embryo Transfer—Daytime Variation and Impact on Live Birth Rates

Introduction: Corpus luteum (CL) produces progesterone (P(4)) and 17-OH progesterone (17-OH P(4)) during the luteal phase. Contrary to P(4), 17-OH P(4) is not supplied as part of the luteal phase support following IVF-treatment. Therefore, measuring endogenous serum 17-OH P(4) levels may more accurately reflect the CL function compared to monitoring serum P(4) concentrations. Objective: To explore the correlation between mid-luteal serum 17-OH P(4) levels and live birth rates and to explore the possible daytime variations in mid-luteal serum 17-OH P(4.) Design: Prospective cohort study. Patients: 614 women undergoing IVF-treatment and fresh embryo transfer. Intervention: All patients had serum 17-OH P(4) measured 7 days after oocyte pick-up (OPU+7). Furthermore, on OPU+7, seven patients underwent repeated blood sampling during daytime to clarify the endogenous daytime secretory pattern of 17-OH P(4). Outcome measure: Live birth rate. Secondary outcome measure: Daytime variation in serum 17-OH P(4) levels. Results: The highest chance of a live birth was seen with mid-luteal 17-OH P(4) between 6.0 and 14.0 nmol/l. The chance of a live birth was reduced below (RD −10%, p = 0.07), but also above the optimal range for 17-OH P(4) (RD −12%, p = 0.04). Patients with diminished CL-function (17-OH P(4) < 6 nmol/l) displayed clinically stable 17-OH P(4) values, whereas patients with 17-OH P(4) levels >6 nmol/l showed random 17-OH P(4) fluctuations during daytime. Conclusion: The association between 17-OH P(4) and reproductive outcomes is non-linear, and the negative effect of excessive CL-secretion seems to be just as strong as the negative effect of a reduced CL-function during the peri-implantation period.