The value of the progesterone-to-estradiol ratio on the day of hCG administration in predicting ongoing pregnancy and live birth rates in normoresponders undergoing GnRH antagonist cycles

Abstract

Objective: To investigate the relationship of the progesterone-to-estradiol (P/E2) ratio on the day of hCG administration with ongoing pregnancy rates in patients with normal ovarian reserve undergoing GnRH antagonist cycles.

Study design: Observational cohort study including 129 women with normal ovarian reserve undergoing the GnRH antagonist protocol at the IVF unit of Ankara University School of Medicine. Receiver operating characteristics (ROC) analysis was performed to determine cut-off values for the P/E2 ratio detrimental to IVF/ICSI-ET outcomes. The ongoing pregnancy rate was the primary outcome measure. Groups were compared using the independent-samples Student's t-test, Mann Whitney and Chi-Square tests. Multivariate logistic regression analysis was used to study the association between the variables and the P/E2 ratio.

Results: The optimal cut-off value for P/E2 ratio in GnRH antagonist cycles was 0.48; ongoing pregnancy rates and live birth rates were found to be significantly higher in patients with P/E2 ratios≤0.48 than those with>0.48 (50% vs 22.4%, p=0.001 and 38.5% vs 19.7%, p=0.02, respectively). In logistic regression analysis, the P/E2 ratio was found to be an independent predictor for pregnancy, but the sensitivity (69%), specificity (61%) and overall accuracy (67%) were low as a predictor test for cycle outcome.

Conclusion: Although a P/E2 ratio≤0.48 on the day of hCG administration was associated with significantly higher ongoing pregnancy and live birth rates, it has poor predictive value for cycle outcome in patients with normal ovarian reserve undergoing GnRH antagonist cycles.

Keywords: GnRH antagonists; Ongoing pregnancy; Progesterone to estradiol ratio.