title: Cryopreservation of supernumerary high quality embryos predicts favorable outcomes for patients undergoing repeated cycles of in vitro fertilization.
abstract: OBJECTIVE
  To determine whether the decline in pregnancy and implantation rates in repeated fresh IVF cycles is associated with the availability of embryo cryopreservation.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Assisted reproductive unit at an academic institution.
  
  
  METHODS
  Women <38 years old (1,037), undergoing nondonor fresh or frozen embryo transfer (FET) cycles between January 1, 2000 and December 31, 2005.
  
  
  METHODS
  In fresh cycles, women used either pituitary desensitization or GnRH antagonists in combination with gonadotropin stimulation protocols before oocyte retrieval. In FET cycles, endometrial development was achieved by oral E(2) and vaginal P after pituitary desensitization. Embryo transfer occurred either on day 3 or on day 5.
  
  
  METHODS
  Implantation and pregnancy rates (PR).
  
  
  RESULTS
  Excluding FET cycles, implantation rates and PRs declined significantly in repeated cycles compared to the initial one. However, women with supernumerary embryos for cryopreservation appeared to produce embryos with higher implantation potential but were excluded from the analysis. When FET cycles were included, there were no significant declines in PRs for at least three repeated cycles.
  
  
  CONCLUSIONS
  Embryo cryopreservation stratifies women with high quality embryos from those with low quality embryos who require repeat fresh attempts, resulting in an accelerated decline in observed PRs and implantation rates.
authors.affiliation: Department of Obstetrics & Gynecology, Division of Reproductive Endocrinology, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA. jw781@columbia.edu
authors.forename: Jeff G
authors.initials: JG
authors.lastname: Wang
authors.forename: Nataki C
authors.initials: NC
authors.lastname: Douglas
authors.forename: Cary
authors.initials: C
authors.lastname: Dicken
authors.forename: Gary S
authors.initials: GS
authors.lastname: Nakhuda
authors.forename: Michael M
authors.initials: MM
authors.lastname: Guarnaccia
authors.forename: Mark V
authors.initials: MV
authors.lastname: Sauer
mesh_terms: D000328:Adult; D000465:Algorithms; D001755:Blastocyst / Q000166:cytology*; D015331:Cohort Studies; D015925:Cryopreservation; D019924:Embryo Disposition; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000175:diagnosis* / Q000628:therapy; D054315:Oocyte Retrieval; D011247:Pregnancy; D018873:Pregnancy Rate; D011379:Prognosis; D011786:Quality Control; D012189:Retrospective Studies; D016896:Treatment Outcome