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.