Gonadotropins are released in a pulsatile fashion at a frequency of between 1 and 2 hours in the follicular phase of the menstrual cycle. Human menopausal gonadotropins are usually administered intramuscularly. We evaluated the gonadal response to intravenous human menopausal gonadotropins administered in a pulsatile fashion over nine treatment cycles in three anovulatory infertile women. Human menopausal gonadotropin pulses in doses up to 12 IU follicle-stimulating hormone at frequencies between 2 to 3 hours over 3 to 17 days resulted in ovulation in five cycles with one pregnancy being conceived. In the ovulatory cycles (5,000 to 10,000 IU of human chorionic gonadotropin was used to induce ovulation), the 17 beta-plasma estradiol level was 961 +/- 128 versus 326 +/- 95 pg/ml (mean +/- SEM) in the anovulatory cycles (p = 0.015). The dose of human menopausal gonadotropins (in ampules of Pergonal, 75 IU of follicle-stimulating hormone and 75 IU of luteinizing hormone) in the intravenous cycles needed to induce ovulation was 12.3 +/- 1.4 versus 20.4 +/- 0.9 for intramuscular cycles (n = 80 in 23 women, p = 0.008). Treatment was well tolerated and without complications. We are continuing to explore the use of this apparently more efficient mode of administering human menopausal gonadotropins to anovulatory patients resistant to other techniques of ovulation induction therapy.