title: Day 2 transfer improves pregnancy outcome in in vitro fertilization cycles with few available embryos.
abstract: OBJECTIVE
  Delaying ET to day 3 to optimize embryo selection is well accepted. However, in cases where there are not enough embryos to perform selection, it is not clear whether there is a difference in clinical outcomes with the day of ET.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Two hundred forty-two fresh IVF/intracytoplasmic sperm injection (ICSI) cycles from 2002-2004, where all generated embryos were transferred irrespective of quality because of an extremely low number of available embryos.
  
  
  METHODS
  In time period 1, ET was on day 3. In time period 2, ET was on day 2.
  
  
  METHODS
  Patient response to stimulation was analyzed along with pregnancy outcome and implantation rate.
  
  
  RESULTS
  Miscarriage rates were decreased, and ongoing pregnancy rates were increased with a day 2 ET in patients <40 years of age.
  
  
  CONCLUSIONS
  In women <40 years of age, the day of transfer is a significant predictor of clinical outcome in cases in which a low number of embryos are available for transfer. The evidence suggests that limiting embryo culture to only 2 days reduces the incidence of miscarriage and increases ongoing pregnancy rates.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, USA.
authors.forename: Shehua
authors.initials: S
authors.lastname: Shen
authors.forename: Mitchell P
authors.initials: MP
authors.lastname: Rosen
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Dobson
authors.forename: Victor Y
authors.initials: VY
authors.lastname: Fujimoto
authors.forename: Charles E
authors.initials: CE
authors.lastname: McCulloch
authors.forename: Marcelle I
authors.initials: MI
authors.lastname: Cedars
mesh_terms: D000328:Adult; D002140:California / Q000453:epidemiology; D004624:Embryo Transfer / Q000706:statistics & numerical data*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000706:statistics & numerical data*; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology* / Q000628:therapy*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D018401:Sample Size; D013997:Time Factors; D016896:Treatment Outcome