title: Does storage time influence postthaw survival and pregnancy outcome? An analysis of 11,768 cryopreserved human embryos.
abstract: OBJECTIVE
  To evaluate the impact of cryopreservation storage duration on embryo survival, implantation competence, and pregnancy outcome.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Academic tertiary-referral infertility center.
  
  
  METHODS
  In vitro fertilization patients and recipients of oocyte donation cycles who had cryopreserved embryos and underwent at least one thaw cycle from 1986 to 2007.
  
  
  METHODS
  None.
  
  
  METHODS
  Postthaw survival proportion and implantation, clinical pregnancy, miscarriage, and live birth rates.
  
  
  RESULTS
  Length of storage time did not have a significant effect on postthaw survival for IVF or oocyte donation cycles, or for embryos frozen at the pronuclear or cleavage stages. There was no significant impact of the duration of storage on clinical pregnancy, miscarriage, implantation, or live birth rate, whether from IVF or oocyte donation cycles. Logistic regression analysis demonstrated that the length of storage time or developmental stage at freezing were not predictive of embryo survival or pregnancy outcome. Only oocyte age, survival proportion, and number of transferred embryos were positive predictors of pregnancy outcome.
  
  
  CONCLUSIONS
  Cryostorage duration did not adversely affect postthaw survival or pregnancy outcome in IVF or oocyte donation patients.
authors.affiliation: Department of Obstetrics and Gynecology, The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Riggs
authors.forename: Jacob
authors.initials: J
authors.lastname: Mayer
authors.forename: Donna
authors.initials: D
authors.lastname: Dowling-Lacey
authors.forename: Ting-Fing
authors.initials: TF
authors.lastname: Chi
authors.forename: Estella
authors.initials: E
authors.lastname: Jones
authors.forename: Sergio
authors.initials: S
authors.lastname: Oehninger
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer; D004622:Embryo, Mammalian; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000628:therapy*; D050498:Live Birth; D016015:Logistic Models; D016017:Odds Ratio; D018587:Oocyte Donation; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D027724:Reproductive Techniques, Assisted / Q000009:adverse effects; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome