title: The association of crown-rump length discordance in twin gestations with adverse perinatal outcomes.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the association between the crown-rump length (CRL) difference in twin gestations and adverse pregnancy outcome.
  
  
  METHODS
  Women with a first trimester ultrasound scan of a twin pregnancy who delivered between June 2000 and March 2006 at Northwestern Memorial Hospital were identified. The association between the difference in CRLs and pregnancy outcomes was explored.
  
  
  RESULTS
  For the 178 twins who were eligible for the study, the median difference in CRLs was 4.2% and the median difference in birthweights was 9.3%. Twins with a CRL difference of >85th percentile (11.1%) were more likely to have discordant birthweights and to have at least 1 of the pair be small-for-gestational age, be admitted to the special care nursery, and have perinatal morbidity.
  
  
  CONCLUSIONS
  CRL differences of >85th percentile are associated with several measures of adverse perinatal outcome.
authors: Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors: Judy
authors: J
authors: Tai
authors: William A
authors: WA
authors: Grobman
mesh_terms: D000328:Adult; D001034:Apgar Score; D001724:Birth Weight; D000013:Congenital Abnormalities / Q000175:diagnosis; D018568:Crown-Rump Length; D004200:Diseases in Twins / Q000175:diagnosis*; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D014427:Twins