Objective: To assess the efficacy of three different GnRH agonist (GnRH-a) stimulation regimens to improve ovarian response in poor responders undergoing IVF. Design: Retrospective cohort study. Setting: Center for Reproductive Health at the University of Cincinnati Medical Center. Patient(s): Women diagnosed as poor responders who presented consecutively from January 1999 to January 2004. Intervention(s): Patients underwent three different stimulation regimens during IVF cycles: 1 stop protocol: GnRH-a 500 μg/d administered from the midluteal phase to the start of menses, then gonadotropins from day 2 of cycle, 2 microdose flare: GnRH-a 20 μg administered twice daily with gonadotropins from day 2 to the day of hCG administration, or 3 regular dose flare: gonadotropins beginning with GnRH-a on day 2 at 1 mg/d for 3 days, followed by 250 μg/d until the day of hCGadministration. Main Outcome Measure(s): Ovarian response, implantation rates, clinical pregnancy and delivery rates. Result(s): Sixty-one IVF cycles were included in the study. None of the comparisons reached statistical significance; however, the microdose group demonstrated a trend toward a higher completed pregnancy rate. Conclusion(s): The microdose flare protocol for poor responders demonstrated a trend toward higher delivery rates. A larger prospective study would need to be performed to determine whether this trend leads to a significant finding in this patient population. Objective: To assess the efficacy of three different GnRH agonist (GnRH-a) stimulation regimens to improve ovarian response in poor responders undergoing IVF. Design: Retrospective cohort study. Setting: Center for Reproductive Health at the University of Cincinnati Medical Center. Patient ( s): Women diagnosed as poor responders who presented consecutively from January 1999 to January 2004. Intervention (s): Patients underwent three different stimulation regimens during IVF cycles: 1 stop protocol: GnRH-a 500 μg / d administered from the midluteal phase to g of twice daily with gonadotropins from day 2 to the day of hCG administration, or 3 regular dose flare: gonadotropins beginning with GnRH-a on day 2 at 1 mg / d for 3 days followed by 250 μg / d until the day of hC Gadministration. Main Outcome Measure (s): Ovarian response, implantation rates, clinical pregnancy and delivery rates. Resul None of the comparisons reached statistical significance; however, the microdose group demonstrated a trend toward a higher completed pregnancy rate. Conclusion (s): The microdose flare protocol for poor responders demonstrated a trend toward higher delivery rates. A larger prospective would would to be performed to determine whether this trend leads to a significant finding in this patient population.