Monitoring gonadotropin-stimulated cycles for in vitro fertilization and embryo transfer.

One hundred fifty-one cycles stimulated with human menopausal gonadotropin (hMG) and/or follicle-stimulating hormone (FSH) were analyzed retrospectively to determine the relationship of the monitoring parameters used: serum estradiol (E2), transvaginal sonographic follicular size, and peripheral biologic estrogen response, with harvests and pregnancies resulting from in vitro fertilization and embryo transfer. Mean +/- SE serum E2 levels were higher on the day of human chorionic gonadotropin (hCG) administration in the miscarriage group (689.4 +/- 27.5 pg/ml) than in the nonpregnant group (527.7 +/- 25.8 pg/ml) (P = 0.018) and highest in the ongoing pregnancy group (734.6 +/- 66.5 pg/ml) (P = 0.003). When two or more preovulatory oocytes (preovs) were retrieved, the mean E2 levels were higher (622.3 +/- 27.3 pg/ml) than if zero or one preov was retrieved (378.4 +/- 43.5 pg/ml) (P = 0.001). The mean diameter of the two largest follicles at the time of hCG administration was significantly greater (14.7 mm) in the group with two or more preovs retrieved than in the group with zero or one preov (13.3 mm) (P = 0.001). The relative probability of achieving a pregnancy was best predicted by the presence of two follicles greater than or equal to 16 mm in diameter on transvaginal ultrasound examination and was 1.63 times greater than that of all patients in this series.