Factors that determine discordant outcome from shared oocytes

Objective: To investigate the factors that may be related to pregnancy in oocyte recipients who shared oocytes from the same donor and showed discordant pregnancy outcome. Design: Matched pair analysis. Setting: WE academic center. Patient(s): Five hundred forty-two oocyte donation cycles that shared oocytes from 197 donors with discordant outcome. Intervention(s): Egg donation and embryo transfer. Main Outcome Measure(s): Pregnancy rate and implantation rate. Result(s): Three hundred sixty-five matched-paired discordant outcome oocyte recipients were analyzed. Pregnant and nonpregnant recipients were similar in terms of age, serum E, levels, endometrial thickness, indications for oocyte donation, and abnormal sperm parameters. No differences were found in the number of oocytes received per patient, fertilization rate, IVF/intracytoplasmic sperm injection (ICSI) distribution, embryo quality, or on embryo transfer difficulty. Conclusion(s): Discordant pregnancy outcome could not be explained by the different egg recipients and cycle factors studied. In addition to chance, other factors must be investigated that could explain discordant outcome in egg recipients sharing oocytes from single donors. (C) 2003 by American Society for Reproductive Medicine.