Management of poor responders: can outcomes be improved with a novel gonadotropin-releasing hormone antagonist/letrozole protocol?

Objective: To compare the efficacy of a microdose GnRH agonist flare (ML) with a GnRH antagonist/letrozole (AL) protocol before IVF-ET in poor responders. Design: Prospective controlled trial. Setting: Private assisted reproductive technology center. Patient(s): Five hundred thirty-four infertile women classified as pastor potential poor responders based on clinic-specific criteria. Intervention(s): Poor responders were prospectively assigned to an ML or AL protocol in a 2:1 ratio, respectively. Main Outcome Measure(s): Results of controlled ovarian hyperstimulation and implantation and ongoing pregnancy rates. Result(s): Patient characteristics were similar between the two protocol groups. There were no significant differences in mean age, number of oocytes, fertilization rates, number of embryos transferred, or embryo score. Peak E-2 levels we're significantly lower in the AL group. Ongoing pregnancy rates were significantly higher in the ML group (52% vs. 37%). Trends toward increased implantation and lower cancellation rates were also noted, but these did not reach statistical significance. Conclusion(s): Quantitative results of stimulation between the NIL and AL protocols were equivalent with the exception of peak E-2 levels. However, the higher ongoing pregnancy rates and trend toward superior implantation rates would suggest that ML re resents a preferred approach for the poor responder. An increased sample size would be necessary to verify these findings.