Different ART outcomes at increasing peak estradiol levels with long and antagonist protocols: retrospective insights from ten years experience.

Purpose: To evaluate the impact of high estradiol (E2) levels on assisted reproductive technologies outcomes in high responders (≥12 oocytes retrieved) according to the controlled ovarian stimulation protocol (COS) used.

Methods: Clinical retrospective evaluation of total, clinical pregnancy and implantation rates in ART cycles performed in high responders according to the COS protocol used (long or antagonist) at Pathophysiology Unit of Human Reproduction and Sperm Bank of Pordenone from June 2000 to December 2010.

Results: In high responders total, clinical and implantation rates were significantly higher in long if compared with antagonist protocol with peak estradiol level ≤3,000 pg/ml; on the contrary there was a significantly higher implantation rate with antagonist than long protocol with peak estradiol >3,000 pg/ml. However in this subgroup of patients total and clinical pregnancy rates showed only a trend favouring antagonist possibly due to a statistical β error.

Conclusions: In high responders long protocol seems to work better than antagonist when peak E2 is lower than 3,000 pg/ml but the opposite may be true for cycles with higher E2 levels.