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 past or 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 were 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 ML 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 represents a preferred approach for the poor responder. An increased sample size would be necessary to verify these findings.