Programming in vitro fertilization retrievals during working days after a gonadotropin-releasing hormone antagonist protocol with estrogen pretreatment: does the length of exposure to estradiol impact on controlled ovarian hyperstimulation outcomes?

Objective: To verify whether a variable number of days beyond the menses of estrogen (E) pretreatment may impact on controlled ovarian hyperstimulation (COH) outcomes and birth rate using a GnRH antagonist protocol. Design: Single center, prospective, nonrandomized study. Setting: Nonacademic fertility unit. Patient(s): A total of 1,080 women, aged 25-38 years, consecutively included (1,603 cycles). Intervention(s): Given 4 mg/d E-2 valerate, started 3 days before the theoretical date of the next menses up to the first day of stimulation (S1). Main Outcome Measure(s): Hormone serum levels, drug exposure, and main IVF outcomes. Result(s): The cancellation rate was similar in the six similarly sized groups according to the number of days with E-2 pretreatment beyond the menses (1-8 days). The mean serum E-2 and LH levels at S1 gradually increased along with E-2 exposure, whereas the mean serum P level decreased. The mean serum E-2 level on the day of hCG administration gradually increased along with E-2 exposure. Serum LH level at S1 correlated significantly and positively to the length of E-2 exposure and to E-2 level on the day of hCG administration. No significant difference was observed for the number of oocytes retrieved and the number of embryos obtained. Women exposed the longest to exogenous E-2 tended to have higher pregnancy rates (PR). Conclusion(s): Extending E-2 pretreatment beyond the menses had no deleterious effect on themain COH outcomes and proved to be slightly beneficial. (Fertil Steril (R) 2011;96:872-6. (C) 2011 by American Society for Reproductive Medicine.)