title: Transfer of refrozen twice-thawed embryos do not decrease the implantation rate.
abstract: OBJECTIVE
  To assess the ability of twice frozen/thawed multi-cell embryos to implant in the human uterus.
  
  
  METHODS
  Fourteen frozen embryo transfer (ET) cycles, in which at least one twice-frozen embryo was thawed for transfer, were matched to frozen ET cycles in which no twice-frozen embryos were thawed. The number of embryos thawed at the pronuclear stage and at the multi-cell stage were matched.
  
  
  RESULTS
  Multi-cell embryos frozen once had a 76.3% survival rate after thaw and those frozen twice had a 74.0% survival rate. For frozen ET cycles that had no twice-frozen embryos, the viable pregnancy and implantation rates were 58.3% and 29.8%, respectively. The corresponding rates for cycles involving at least one twice-frozen embryo were 50.0% and 25.5%, respectively.
  
  
  CONCLUSIONS
  The inclusion of twice-frozen embryos in the embryo pool did not reduce the implantation rate.
authors.affiliation: The University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Check
authors.forename: D
authors.initials: D
authors.lastname: Brittingham
authors.forename: K
authors.initials: K
authors.lastname: Swenson
authors.forename: C
authors.initials: C
authors.lastname: Wilson
authors.forename: D
authors.initials: D
authors.lastname: Lurie
mesh_terms: D000328:Adult; D015925:Cryopreservation; D004624:Embryo Transfer; D005260:Female; D005615:Freezing; D006801:Humans; D016555:Matched-Pair Analysis; D011247:Pregnancy; D018873:Pregnancy Rate