title: Extended embryo culture is not associated with increased adverse obstetric or perinatal outcome.
abstract: OBJECTIVE
  We sought to compare obstetric and perinatal outcomes of singletons born after extended embryo culture and a single blastocyst stage embryo vs a single cleavage stage embryo transfer.
  
  
  METHODS
  This was a retrospective cohort study of 1543 fresh single embryo transfers using nondonor oocytes in women ≤40 years old from December 2008 through December 2012 at the reproductive unit of McGill University Health Center. The main outcome measures were perinatal outcomes including birthweight, low birthweight, small for gestational age, preterm delivery, preeclampsia, placental abruption, and neonatal complications. Covariates were maternal age, body mass index, smoking, cause of infertility, parity, and sex of the baby.
  
  
  RESULTS
  Transfers of 693 fresh single cleavage embryos and 850 fresh single blastocysts resulting in 564 pregnancies and 381 singleton deliveries were analyzed. Blastocyst transfer resulted in a higher clinical pregnancy rate (50.1% and 19.9%) and live birth rate (33.5% and 13.8%) compared to cleavage embryo transfer, respectively (P < .001). Multivariate analyses for pregnancy revealed no increased risk of maternal or neonatal complications in pregnancies resulting from extended embryo culture.
  
  
  CONCLUSIONS
  Live births resulting from extended embryo culture and a single blastocyst transfer are not associated with increased adverse obstetric and perinatal outcome compared to live births from a single cleavage embryo transfer in women ≤40 years old.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada. Electronic address: orongalia@gmail.com.
authors.forename: Galia
authors.initials: G
authors.lastname: Oron
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Tamar
authors.initials: T
authors.lastname: Sokal-Arnon
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Weon-Young
authors.initials: WY
authors.lastname: Son
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Ezgi
authors.initials: E
authors.lastname: Demirtas
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: William
authors.initials: W
authors.lastname: Buckett
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Atef
authors.initials: A
authors.lastname: Zeadna
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Hananel
authors.initials: H
authors.lastname: Holzer
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Togas
authors.initials: T
authors.lastname: Tulandi
mesh_terms: D000328:Adult; D001755:Blastocyst; D002970:Cleavage Stage, Ovum; D015331:Cohort Studies; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D006801:Humans; D007231:Infant, Newborn; D007246:Infertility / Q000628:therapy; D050498:Live Birth / Q000453:epidemiology*; D008297:Male; D015999:Multivariate Analysis; D010053:Ovary / Q000166:cytology / Q000502:physiology; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies
keywords: blastocyst transfer; pregnancy complications; single embryo transfer; transfer day