High progesterone/estradiol ratio in follicular fluid at oocyte aspiration for in vitro fertilization as a predictor of possible pregnancy.

Eighteen women undergoing in vitro fertilization (IVF) procedures were studied. All had optimal (900 to 1600 pg/ml) peak serum estradiol (E2) response to the same stimulation regimen with clomiphene citrate and menotropins; fertilization rate was above 64%; and two to four embryos in two to eight cell stages were replaced in each patient. All were considered to have optimal chances for conception. The authors compared progesterone (P), E2, and P/E2 ratio in serum and follicular fluid (FF) at the time of oocyte aspiration in eight patients who conceived (group I) and ten who did not (group II). Mean serum P and E2 levels and serum P/E2 ratio were not significantly different between the groups. In contrast, mean FF P concentrations (ng/ml) were significantly (P less than 0.05) higher in group I (9721 versus 5385), as was FF P/E2 ratio (19.0 versus 11.8; P less than 0.02). There was no significant difference in mean FF E2 concentrations between the groups. These data indicate that in IVF cycles with optimal serum E2 response to the stimulation protocol, FF P and P/E2 ratio at the time of oocyte aspiration may be predictive of subsequent implantation and pregnancy.