Poor responders in in vitro fertilization (IVF) therapy: the challenge continues.

Poor responders represent more than a third of women undergoing assisted reproduction. Typically they are patients with advanced maternal age and low ovarian reserve. However, there is a younger group that unexpectedly demonstrates impaired response to controlled ovarian hyperstimulation. The etiologies in many of these cases are still unclear. In our program, the determination of basal cycle day 3 serum FSH, LH and E2 levels, measurement of AMH, and the estimation of the basal antral follicular count by transvaginal ultrasonography, are the preferred screening tests for ovarian reserve in all IVF patients, and together with the woman's age, determine the ovarian stimulation regimen to be chosen for the cycle treatment. In spite of a -variety of protocols and adjuvant therapies of unproven benefit, these patients have compromised outcomes and continue to represent a challenge to reproductive endocrinologists.