UTERINE PREPARATION WITH ESTROGEN FOR OOCYTE DONATION - ASSESSING THEEFFECT OF TREATMENT DURATION ON PREGNANCY RATES

Objective: To assess the effect of the duration of uterine preparation with E(2) on pregnancy rates (PRs) in oocyte donation. Design: A retr ospective study. Setting: NF-ET Unit, oocyte donation program. Patient s: Four hundred eleven patients undergoing 865 ET cycles after oocyte donation. Uterine preparation consisted of 6 mg/d E(2) valerate. The d uration of treatment varied according to the availability of the oocyt es for donation. Progesterone, 100 mg/d, was added upon oocyte retriev al. Patients were divided into seven groups according to the duration of uterine preparation with E(2), in 5-day ranks. Main Outcome Measure s: Pregnancy rates per ET according to the duration of uterine prepara tion. Results: No differences were noted in the mean age, number of oo cytes received, fertilization rates, or number of embryos transferred when comparing all groups. Pregnancy rates ranged from 19% to 27% for E(2) treatment-of 5 to 35 days. Conclusion: Endometrial preparation in anonymous oocyte donation programs is achieved with continuous admini stration of E(2) until oocytes become available. Our results show that this treatment may be extended for as long as 5 weeks with no signifi cant decrease in PRs.