Cumulative exposure to high estradiol levels during the follicular phase of IVF cycles negatively affects implantation.

PurposeTo investigate the effect of the cumulative exposure to estradiol (E(2)) during the follicular phase on IVF outcome.MethodsPatients were stimulated with recombinant FSH after GnRH agonist suppression and had a day 3-embryo transfer. Estrogen exposure was determined as the area under the curve (AUC) for serum E(2) levels measured from the first day of stimulation through the day after hCG administration.ResultsE(2) AUC thresholds for 10th and 90th percentiles were 4704 pg/ml and 16338 pg/ml, respectively. The pregnancy and implantation rates were highest in the 10th-90th percentile group, and were statistically higher in this group than in the >90th percentile group (54.6% vs. 33.3% and 24.8% and 12.9%, respectively, for pregnancy and implantation rates, P < 0.05). Recovered mature oocytes, fertilization, and number and mean score of transferred embryos were similar.ConclusionsHigh cumulative E(2) exposure during the follicular phase of IVF cycles has detrimental effects on implantation.