Pharmacologic hypophysectomy was induced with a subcutaneous injection of leuprolide acetate before the administration of exogenous gonadotropins for multiple follicle development in 27 women who had previously responded poorly to conventional controlled ovarian hyperstimulation (COH). Pituitary desensitization occurred within 6 days and concurrent COH with exogenous gonadotropins resulted in an enhanced yield of oocytes in comparison to previous COH attempts (P less than 0.05). Fertilization and pregnancy rates also were higher with gonadotropin-releasing hormone agonist (GnRHa) treatment (P less than 0.01). The administration of leuprolide acetate effectively suppressed endogenous gonadotropin secretion when initiated in the follicular or luteal phase of the menstrual cycle. GnRHa therapy can appreciably facilitate the management of gonadotropin therapy, and increase the probability of oocyte collection and pregnancy.