Assessment of ovulation by ultrasound and estradiol levels during spontaneous and induced cycles.

Both Graafian follicle growth and subsequent ovulation were studied in 45 menstrual cycles of 28 patients by the estimation of plasma estradiol levels and by the measurement of follicle size and number by ultrasound. Twenty spontaneous ovulatory cycles were studied as controls compared with twenty cycles in which ovulation was induced by clomiphene and five cycles in which ovulation was induced by human pituitary gonadotropin. The means of the peak estradiol levels during the cycles in which one follicle was present were 1553.1 +/- 87.8 pmoles/liter in the spontaneous cycles and 2296.8 +/- 163.4 pmoles/liter in the clomiphene-treated cycles. Ultrasound was shown to be complementary to endocrine profiles because the number and diameter of Graafian follicles could be measured accurately by this technique.