title: Impact of head-to-abdominal circumference asymmetry on outcomes in growth-discordant twins.
abstract: OBJECTIVE
  Our aim was to evaluate head-to-abdominal circumference asymmetry as a marker for adverse outcomes in growth-discordant twins.
  
  
  METHODS
  We conducted a retrospective cohort study of asymmetric and symmetric twins with > or =25% growth discordance, comparing their outcomes with those in concordant symmetric twins. Growth was termed asymmetric on the basis of a head circumference/abdominal circumference ratio at > or =95th percentile on ultrasonography performed < or =4 weeks before delivery.
  
  
  RESULTS
  We evaluated 572 twin pairs. Asymmetric discordant twins were more likely than symmetric concordant twins to be delivered at < or =34 weeks' gestation (57% vs. 27%), to require intubation (36% vs. 7%), to remain in intensive care >1 week (36% vs 3%), and to have an outcome composite that included respiratory morbidity, intraventricular hemorrhage, sepsis, or neonatal death (29% vs 6%), all P<.05. Symmetric discordant and symmetric concordant twins had similar outcomes.
  
  
  CONCLUSIONS
  Discordant twins with head-to-abdominal circumference asymmetry have an increased risk of morbidity. Moreover, in the absence of asymmetry, outcomes are comparable among discordant and concordant twins.
authors.affiliation: Department of Obstetrics and Gynecology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Dashe
authors.forename: D D
authors.initials: DD
authors.lastname: McIntire
authors.forename: R
authors.initials: R
authors.lastname: Santos-Ramos
authors.forename: K J
authors.initials: KJ
authors.lastname: Leveno
mesh_terms: D000005:Abdomen / Q000196:embryology*; D015331:Cohort Studies; D005314:Embryonic and Fetal Development; D005260:Female; D005333:Fetus / Q000033:anatomy & histology* / Q000502:physiology*; D006257:Head / Q000196:embryology*; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D012189:Retrospective Studies; D012307:Risk Factors; D014427:Twins