title: Impact of fresh-cycle variables on the implantation potential of cryopreserved-thawed human embryos.
abstract: OBJECTIVE
  To compare the clinical outcomes of cryopreservation according to the indications for freezing and the outcomes of the fresh cycle from which the embryos were derived.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Private assisted-reproduction unit.
  
  
  METHODS
  Three thousand, three hundred and sixty-eight embryos in 702 frozen-thawed embryo transfer (ET) cycles.
  
  
  METHODS
  Clinical outcomes of frozen-thawed ET cycles in which embryos were derived from fresh conception cycles (n = 436), from fresh nonconception cycles (n = 180), or where the fresh cycle was cancelled due to impending ovarian hyperstimulation syndrome (OHSS) (n = 86).
  
  
  METHODS
  Cryosurvival, clinical pregnancy, and implantation rates.
  
  
  RESULTS
  Despite similar cryosurvival rates and the transfer of a similar number of embryos, significantly higher clinical pregnancy and implantation rates were obtained in the fresh-conception and OHSS groups. The implantation potential of frozen-thawed embryos that were not selected in a prior fresh cycle was comparable to that of embryos selected for fresh transfer.
  
  
  CONCLUSIONS
  The success of frozen-thawed ET depends on the outcome of fresh ET and the indications for cryopreservation. Success is similar to that of fresh ET cycles in patients who had all their embryos frozen due to impending OHSS.
authors.affiliation: Assisted Reproduction Unit, American Hospital of Istanbul, Nisantasi, Istanbul, Turkey. burman@superonline.com <burman@superonline.com>
authors.forename: Bulent
authors.initials: B
authors.lastname: Urman
authors.forename: Basak
authors.initials: B
authors.lastname: Balaban
authors.forename: Kayhan
authors.initials: K
authors.lastname: Yakin
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000706:statistics & numerical data*; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology* / Q000628:therapy*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D014421:Turkey / Q000453:epidemiology