Purpose: To determine if too high of a level of progesterone at the time of peak follicular maturation of donors adversely affects pregnancy or implantation rates of recipients. Methods: A retrospective cohort analysis was performed on donor egg recipients. Pregnancy rates were calculated according to ranges of five serum progesterone (P) levels based on two standard deviations before and above the mean. Results: No adverse effect was found in recipients whose donors had serum P levels between 2.47 and 3.41 ng/ml. There may have been a slightly lower pregnancy rate in recipients whose donors had seen P levels over 3.41 but there were only seven patients in that group and there still was a live delivered pregnancy rate of 28.6% per transfer. Conclusions: The main adverse effect of a premature rise of progesterone in women making multiple follicles with gonadotropin stimulation seems to be on the endometrium. There appear to be enough follicles not affected by the progesterone to recommend proceeding with oocyte retrieval in the donor so as not to waste money on expensive medication and monitoring.