title: Factors that determine discordant outcome from shared oocytes.
abstract: 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.
  
  
  METHODS
  Matched pair analysis.
  
  
  METHODS
  IVF academic center.
  
  
  METHODS
  Five hundred forty-two oocyte donation cycles that shared oocytes from 197 donors with discordant outcome.
  
  
  METHODS
  Egg donation and embryo transfer.
  
  
  METHODS
  Pregnancy rate and implantation rate.
  
  
  RESULTS
  Three hundred sixty-five matched-paired discordant outcome oocyte recipients were analyzed. Pregnant and nonpregnant recipients were similar in terms of age, serum E(2) 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Instituto Valenciano de Infertilidad, Madrid, Spain. jgvelasco@ivi.es
authors.forename: Juan A
authors.initials: JA
authors.lastname: Garcia-Velasco
authors.forename: Verónica
authors.initials: V
authors.lastname: Isaza
authors.forename: Cinthia
authors.initials: C
authors.lastname: Caligara
authors.forename: Antonio
authors.initials: A
authors.lastname: Pellicer
authors.forename: José
authors.initials: J
authors.lastname: Remohí
authors.forename: Carlos
authors.initials: C
authors.lastname: Simón
mesh_terms: D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D010064:Embryo Implantation / Q000502:physiology*; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D018587:Oocyte Donation; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome
chemical_list: D004958:Estradiol