Characteristics of human follicular fluid associated with successful conception after in vitro fertilization

In 23 follicular fluids (FF) each yielding an oocyte known to result in a clinical pregnancy after in vitro fertilization, the following substances were measured: free and total concentrations of estradiol (E2), progesterone (P4), testosterone (T), androstenedione (A), immunoreactive inhibin, insulin-like growth factor-binding protein-1, alpha 1-antitrypsin, and placenta protein-14. In addition, FF volume and follicular diameter at the time of oocyte recovery were recorded. The characteristics of these pregnancy-associated follicles were compared with those of FF obtained from women who failed to conceive after embryo transfer. The FF were collected from 14 women who became pregnant and 14 women who did not conceive. The ultrashort GnRH agonist protocol was used for ovarian stimulation. Pregnancy was associated with follicles showing a significantly higher E2/T ratio than follicles in which the oocyte failed to implant or did not cleave in vitro (P < 0.01). In addition, FF volume and follicular diameter w...