title: The efficacy of the transfer of twice frozen-thawed embryos with the vitrification method.
abstract: OBJECTIVE
  To confirm the clinical benefits of recryopreserved, twice-thawed embryo transfer (ET).
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Private fertility clinic.
  
  
  METHODS
  Forty-nine women whose embryos had been refrozen after a previous frozen-thawed ET.
  
  
  METHODS
  None.
  
  
  METHODS
  Comparison of implantation and pregnancy rates of twice-cryopreserved, twice-thawed embryos versus once-cryopreserved, once-thawed embryos.
  
  
  RESULTS
  The pregnancy rate per ET cycle was 27.8% in the refrozen group and 25.9% in the control group (no statistically significant difference). The implantation rate was 25.0% in the refrozen group and 19.3% in the control group (no statistically significant difference).
  
  
  CONCLUSIONS
  The refreezing of supernumerary embryos can prevent ovarian hyperstimulation syndrome in stimulated patients and in those who have experienced repeated failed pregnancies. If unexpected supernumerary embryos are available for recryopreservation after frozen-thawed ET, these embryos may be revitrified for a future transfer.
authors.affiliation: St. Luke Clinic, Tsumori, Tsumori, Oita, Japan. lukelab@oct-net.ne.jp
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kumasako
authors.forename: Eiko
authors.initials: E
authors.lastname: Otsu
authors.forename: Takafumi
authors.initials: T
authors.lastname: Utsunomiya
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Araki
mesh_terms: D000328:Adult; D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer; D004622:Embryo, Mammalian; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D016896:Treatment Outcome