Late follicular progesterone to estradiol ratio is not influenced by protocols or gonadotropins used

OBJECTIVE Increased progesterone level during follicular phase seemed to be associated with decreased pregnancy rate. STUDY DESIGN AND METHODS A prospective cohort study, 1.1.2012 - 31.8.13. The Progesterone (P) and Progesterone/Estrogen (P/E2) level on ovulation induction day were compared between the protocols and the different gonadotropins used. Roc analysis was calculated to determine the cutoff of P/E2 to predict delivery rates. P/E2 ratio was calculated as PX1000/e2 level. MAIN RESULTS One hundred thirty-nine patients were enrolled to the study. No difference in the P level at hCG stimulation day between different protocols, however, E2 and P/E2 ratio were significantly lower in the long protocol compare with antagonist protocol 1757.7 ± 923.2 vs. 1342.9 ± 1223; P = 0.003 and 0.48 ± 0.31 vs. 0.83 ± 0.87; P = 0.038). The endometrium was significantly thicker in the long group compare with short and antagonist. Significantly more top-quality embryos (TOP) were achieved in the antagonist group. Comparable results between the types of gonadotropins used in regards with cycle characteristics and pregnancy and delivery rates. The P/E2 ratio which can predict live birth rate was found to be 0.45, AUC = 0.632, p = 0.02 and 95 % CI 0.525-0.738 and a significantly higher pregnancy and delivery rates at a P/E2 bellow 0.45. CONCLUSION Endometrial receptivity is determined by the complex interactions of E2 and P.