Follicular fluid estradiol and progesterone are markers of preovulatory oocyte quality.

Follicular fluid estradiol (FF E2) and progesterone (P) have previously been shown to vary with the maturation of the follicle. A profile of follicular fluid E2 and P was obtained from follicles of 19 preovulatory oocytes, which resulted in normal term pregnancies from single embryo transfers. A narrow band was defined around the linear regression line E2/P = 1.2 X 10(-2) + 1.57 X 10(-4) E2, r = 0.806, P less than 0.01, when E2/P was plotted versus E2 that included 84.2% of these oocytes. Eleven of the 19 pregnancies were clustered between an E2 of 240 to 460 ng/ml and an E2/P ratio of 0.044 to 0.084. Sixty-eight patients undergoing in vitro fertilization and embryo transfer were studied. A significantly greater number of preovulatory follicles from the fertilized, cleaved, and pregnant group (10 of 40) was found in the cluster than from the fertilized, cleaved, but not pregnant group (4 of 46; P = 0.04) and fertilized but not cleaved group (0 of 13; P = 0.04). Significantly more pregnant patients (14 of 20) had a preovulatory follicle within the band than nonpregnant patients (11 of 36) (P less than .02), as well as in the cluster (10 of 20), compared with 4 of 36, respectively (P less than 0.01). It may be concluded that a range of FF E2 and E2/P values define a stage of maturation that is compatible with successful pregnancies.