title: Day 4 versus day 3 embryo transfer: a prospective study of clinical outcomes.
abstract: OBJECTIVE
  To compare the clinical outcomes after day 4 or day 3 embryo transfers in controlled ovarian hyperstimulation-IVF/intracytoplasmic sperm injection (ICSI) cycles.
  
  
  METHODS
  Prospective randomized study.
  
  
  METHODS
  Center for Human Reproduction, 'Genesis Athens' Clinic (private gynecological and surgical clinic), Athens, Greece.
  
  
  METHODS
  Three hundred fifty women with primary infertility and indication for IVF/ICSI treatment. Patients were randomly allocated to day 4 or day 3 embryo transfer.
  
  
  METHODS
  Controlled ovarian hyperstimulation, oocyte retrieval, IVF/ICSI, embryo transfer.
  
  
  METHODS
  Implantation rate; clinical, ongoing, and multiple pregnancy rates.
  
  
  RESULTS
  A trend toward higher clinical and ongoing pregnancy rates was noted after day 4 embryo transfers. Implantation and multiple pregnancy rates were comparable after day 4 or day 3 embryo transfers.
  
  
  CONCLUSIONS
  The transfer of day 4 embryos in IVF/ICSI cycles may result in favorable implantation and pregnancy rates which are at least comparable to those after the transfer of day 3 embryos.
authors.affiliation: Center for Human Reproduction, Genesis Athens Clinic, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Pantos
authors.forename: Evangelos
authors.initials: E
authors.lastname: Makrakis
authors.forename: Margaret
authors.initials: M
authors.lastname: Chronopoulou
authors.forename: Maria
authors.initials: M
authors.lastname: Biba
authors.forename: Anastasios
authors.initials: A
authors.lastname: Perdikaris
authors.forename: Alex
authors.initials: A
authors.lastname: Dafereras
mesh_terms: D000328:Adult; D046149:Embryo Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000628:therapy*; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors; D016896:Treatment Outcome