title: Clinical outcome of day 2 versus day 3 embryo transfer using serum-free culture media: a prospective randomized study.
abstract: OBJECTIVE
  The objective was to evaluate whether extending the embryo culture period from 2 to 3 days would yield a more optimal selection of viable embryos, thereby increasing the implantation and live birth rates.
  
  
  METHODS
  Patients undergoing in vitro fertilization with at least one oocyte fertilized were prospectively randomized to 2 or 3 days of embryo culture in serum-free media. On the basis of their morphology and cleavage rate, a maximum of three embryos was selected for transfer.
  
  
  RESULTS
  Embryos transferred on day 2 or day 3 were similar morphologically, however, a higher proportion of retarded embryos was observed on day 3. The implantation rate was 15.8 and 14.3% for day 2 and day 3 transfers, respectively. The increase in live birth rate from 18.5 to 22.6%, possibly suggesting a better embryo selection on day 3, was not statistically significant.
  
  
  CONCLUSIONS
  Extending the embryo culture period from 2 to 3 days had no effect on implantation and live birth rates.
authors.affiliation: Department of Obstetrics and Gynecology, National Hospital, University of Oslo, Norway.
authors.forename: G
authors.initials: G
authors.lastname: Ertzeid
authors.forename: P O
authors.initials: PO
authors.lastname: Dale
authors.forename: T
authors.initials: T
authors.lastname: Tanbo
authors.forename: R
authors.initials: R
authors.lastname: Storeng
authors.forename: E
authors.initials: E
authors.lastname: Kjekshus
authors.forename: T
authors.initials: T
authors.lastname: Abyholm
mesh_terms: D001723:Birth Rate; D016895:Culture Media, Serum-Free; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D006801:Humans; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D016895:Culture Media, Serum-Free