Human gonadotropin therapy. I. Serum estradiol and progesterone patterns during conceptual cycles

Hormone patterns during 43 conceptual cycles induced by human gonadotropins in 37 women with anovulatory infertility were analyzed. The treatment was monitored by daily determinations of estradiol (E2) in serum. The incidence of both multiple pregnancies and abortions during the gonadotropin therapy was high (30%). When the hormone patterns during the human menopausal gonadotropin-induced conceptual cycles were compared with spontaneous conceptual cycles, it became evident that the ovaries were hyperstimulated during the follicular and luteal phases of the induced cycle. The mean serum E2 level at induction of ovulation did not differ between treatment courses resulting in single or multiple pregnancies. The endogenous estrogen secretion at the initiation of treatment was lower in the multiple pregnancy group than in the single pregnancy group. The active phase, i.e., when the estrogens progressively increase during the late follicular phase of the induced cycle, was found to be prolonged in the multiple pregnancy group. The prolonged follicular stimulation by human menopausal gonadotropin might explain why multiple ovulations and pregnancies occur. Thus, both the duration of the active phase of follicular stimulation and the E2 level at the day of induction of ovulation by human chorionic gonadotropin should be determined for optimal monitoring of human gonadotropin therapy.