OBJECTIVE: To evaluate the pregnancy results of an ovarian hyperstimulation protocol for IVF-ET that combines GnRH agonist down-regulation, cessation of GnRH agonist therapy with the onset of menstruation, and high-dose gonadotropin administration in low responders. DESIGN: Prospective analysis. SETTING: Academic IVF program. PATIENT(S): One hundred eighty-two low responders undergoing 224 IVF-ET cycles. INTERVENTION(S): Down-regulation was obtained with the administration of leuprolide acetate beginning in the midluteal phase and ending with the onset of menses. Daily administration of 6 ampules of FSH alone or in combination with hMG was initiated on cycle day 3. MAIN OUTCOME MEASURE(S): Stimulation characteristics and pregnancy rates (PRs) were compared between fresh cycles in which pure FSH alone was used and 35 cycles in which a combination of FSH and hMG was administered. RESULT(S): The clinical PR per transfer, the ongoing PR per transfer, and the implantation rate were 32%, 24%, and 9%, respectively. No differences were noted between cycles in which pure FSH alone was used in comparison with cycles in which a combination of FSH and hMG was administered. CONCLUSION(S): Short-term ovarian suppression begun in the luteal phase and discontinued with the onset of menses followed by high-dose stimulation with gonadotropins yields favorable pregnancy results in low responders.