Percentile curves of serum estradiol levels during controlled ovarian stimulation in 905 cycles stimulated with recombinant FSH show that high estradiol is not detrimental to IVF outcome.

BACKGROUND High, normal and poor responders are usually defined by reference to subjectively selected estradiol E2 levels at days 4-6 and the day of hCG administration (d-hCG). The purpose of this study was to use E2 percentile curves from day 5 until d-hCG to determine high, normal and poor responders, and to predict IVF outcome. METHODS In this retrospective study, 762 patients underwent 905 cycles with a GnRH agonist/recombinant FSH short protocol. They were divided into three groups according to their age. Percentile E2 curves according to E2 levels were plotted. High responders were those patients with E2 levels above the 90th percentile, normal responders had E2 between the 10th and 90th percentiles, and poor responders had E2 below the 10th percentile. RESULTS IVF outcome, expressed as number of oocytes, total embryos obtained and number of high grade embryos, was significantly better for patients with E2 above the 90th percentile at d-hCG for the three age groups and at day 5 for group A (<35 years). Pregnancy rates were higher for high responders, but the difference did not reach statistical significance. CONCLUSIONS Percentile curves can be useful in controlled ovarian stimulation cycles to define high, normal and poor responders, and also to predict IVF outcome.