title: Obstetric and perinatal outcome from single cleavage transfer and single blastocyst transfer: a matched case-control study.
abstract: OBJECTIVE
  To evaluate a possible relationship between extended embryo culture and outcome of pregnancies resulting from single embryo transfers (SETs).
  
  
  METHODS
  A retrospective matched case-control study Setting: University fertility center Patients: About 106 live births from single cleavage embryo transfers were matched 1:2 with 212 live births from single blastocyst transfers.
  
  
  METHODS
  A cohort of 3522 fresh SETs using non-donor oocytes in women ≤40 years old from August 2010 to December 2013. Live births were matched by maternal age, body mass index, smoking and parity. Adjustments were made for gender of the baby and embryo quality. Obstetric and perinatal outcomes including birth weight, low birth weight, small for gestational age, preterm delivery, preeclampsia, placental abruption and neonatal complications were compared.
  
  
  RESULTS
  Matched live birth outcomes showed no increased risk of obstetric or perinatal complications in pregnancies resulting from single blastocyst transfers compared to single cleavage transfers.
  
  
  CONCLUSIONS
  Extended culture was not associated with increased adverse obstetric and perinatal outcome in pregnancies resulting from fresh SETs in this study.
authors.affiliation: Department of Obstetrics and Gynecology, McGill University , Montreal, QC , Canada.
authors.forename: Galia
authors.initials: G
authors.lastname: Oron
authors.forename: Dan
authors.initials: D
authors.lastname: Nayot
authors.forename: Weon-Young
authors.initials: WY
authors.lastname: Son
authors.forename: Hananel
authors.initials: H
authors.lastname: Holzer
authors.forename: William
authors.initials: W
authors.lastname: Buckett
authors.forename: Togas
authors.initials: T
authors.lastname: Tulandi
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D050498:Live Birth; D007744:Obstetric Labor Complications; D011247:Pregnancy; D012189:Retrospective Studies; D056826:Single Embryo Transfer / Q000379:methods* / Q000706:statistics & numerical data
keywords: Blastocyst; cleavage; live births pregnancy outcome; single embryo transfer