Ratio of progesterone-to-number of follicles as a prognostic tool for in vitro fertilization cycles

To establish a ratio of the P level to the number of follicles (P/F ratio) on the day of human chorionic gonadotropin (hCG) administration and to evaluate whether this ratio is associated with in vitro fertilization (IVF) outcome.

This study was conducted between January 2012 and June 2013. A total of 337 patients with cleavage-stage day-3 fresh embryo transfer with P levels ≤1.5 ng/mL on the day of hCG administration were included in the study. The main outcome was ongoing pregnancy rate.

The P/F ratio was calculated according to the equation (P[ng/mL]/number of follicles) on the day of final oocyte maturation. Using ROC, we established a cut-off level of 0.075 for the P/F ratio. The area under the curve (AUC) (0.756; 95 % confidence interval [CI]: 0.704–0.807) indicated that it was a good prognostic test. In group 1 (patients under 36 years old), the ongoing pregnancy rates were 57 and 30 % for patients with P/F ratios ≤ .075 and > .075, respectively, (p = 0.003). In group 2 (patients between 36 and 39 years old), the ongoing pregnancy rates were 58 % and 17 % (p = 0.001) for patients with P/F ratios ≤ .075 and > .075, respectively. In group 3 (patients ≥ 40 years old), the ongoing pregnancy rates were 41.7 and 10.9 % (p = 0.001) for patients with P/F ratios ≤ .075 and > .075, respectively.

The P/F ratio is a good prognostic test for predicting IVF outcome that can correlate the P level with ovarian response.