title: Clinical outcome of day 2 versus day 5 transfer in cycles with one or two developed embryos.
abstract: OBJECTIVE
  To determine whether extended culture of embryos to blastocysts has any benefit in cycles with only one or two created embryos.
  
  
  METHODS
  Retrospective analysis of cycles comparing outcomes of day 2 and day 5 transfers. Our day 2 group was from the year 1999 and our day 5 group, from the year 2000.
  
  
  METHODS
  Assisted reproductive technology program of a teaching hospital.
  
  
  METHODS
  All patients, irrespective of age, who had developed one or two embryos.
  
  
  METHODS
  Stimulated IVF, intracytoplasmic sperm injection, or testicular sperm extraction and intracytoplasmic sperm injection cycles with 2-day culture in universal IVF medium (n = 133) or 5-day culture in BlastAssist media (MediCult, Jyllinge, Denmark; n = 132).
  
  
  METHODS
  Pregnancy, implantation, and take-home baby rates.
  
  
  RESULTS
  In the groups of 2-day and 5-day culture, embryo transfer was performed in 98% and in 57% of cycles, respectively. However, the total implantation rate per created embryo (18% vs. 18%), the pregnancy rate per cycle (23% vs. 21%), and the take-home baby rate (69.4% vs. 71.4%) did not differ between the day 2 and day 5 groups.
  
  
  CONCLUSIONS
  Extended culture of embryos does not improve or decrease their capacity for implantation but only allows for better selection and is therefore not necessary in cycles with fewer than three embryos.
authors.affiliation: Department of Reproductive Medicine and Gynecologic Endocrinology, Maribor Teaching Hospital, Maribor, Slovenia. borut.kov@sb-mb.si
authors.forename: Borut
authors.initials: B
authors.lastname: Kovacic
authors.forename: Veljko
authors.initials: V
authors.lastname: Vlaisavljević
authors.forename: Milan
authors.initials: M
authors.lastname: Reljic
authors.forename: Vida
authors.initials: V
authors.lastname: Gavrić Lovrec
mesh_terms: D000328:Adult; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors