title: Do very preterm twins and singletons differ in their neurodevelopment at 5 years of age?
abstract: OBJECTIVE
  Twins have inconsistently shown poorer outcomes than singletons. Although a high proportion of twins are born very preterm, data are sparse on the long-term outcomes in very preterm twins. The objective of this study was to compare mortality and neurodevelopmental outcomes of very preterm singletons and twins and to study outcomes in relation to factors specific to twins.
  
  
  METHODS
  Birth cohort study Etude Epidemiologique sur les Petits Ages Gestationnels (EPIPAGE).
  
  
  METHODS
  Nine regions in France.
  
  
  METHODS
  All very preterm live births occurring from 22 to 32 weeks of gestation in all maternity wards of nine French regions in 1997 (n=2773).
  
  
  METHODS
  Neurodevelopmental status, including cerebral palsy, and a cognitive assessment with the Kaufman Assessment Battery for Children, with scores on the Mental Processing Composite (MPC) scale, was available for 1732 and 1473 children at 5 years of age, respectively.
  
  
  RESULTS
  Among live births, twins had higher hospital mortality than singletons (adjusted (a)OR: 1.4 (95% CI 1.1 to 1.9)). Among survivors, there was no crude difference at 5 years between twins and singletons in the prevalence of cerebral palsy (8.0% vs 9.1%, respectively), MPC <70 (9.5% vs 11.1%) and mean MPC (94.6 vs 94.4). However, after adjustment for sex, gestational age, intrauterine growth restriction and social factors, twins were more likely to have lower MPC scores (mean difference: -2.4 (95% CI-4.8 to 0.01)). Live born twins had a higher risk of mortality when birth weight discordance was present (aOR:2.9 (95% CI 1.7 to 4.8)), but there were no differences in long-term outcomes.
  
  
  CONCLUSIONS
  Compared with very preterm singletons, twins had higher mortality, no difference with respect to severe deficiencies, but slightly lower MPC scores at 5 years.
authors.affiliation: Epidemiology and Biostatistics, EHESP Rennes, Sorbonne Paris Cité, , Rennes, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Bodeau-Livinec
authors.forename: Jennifer
authors.initials: J
authors.lastname: Zeitlin
authors.forename: Béatrice
authors.initials: B
authors.lastname: Blondel
authors.forename: Catherine
authors.initials: C
authors.lastname: Arnaud
authors.forename: Jeanne
authors.initials: J
authors.lastname: Fresson
authors.forename: Antoine
authors.initials: A
authors.lastname: Burguet
authors.forename: Damien
authors.initials: D
authors.lastname: Subtil
authors.forename: Stéphane
authors.initials: S
authors.lastname: Marret
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Rozé
authors.forename: Laetitia
authors.initials: L
authors.lastname: Marchand-Martin
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Ancel
authors.forename: Monique
authors.initials: M
authors.lastname: Kaminski
mesh_terms: D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D015331:Cohort Studies; D002658:Developmental Disabilities / Q000453:epidemiology*; D005260:Female; D005602:France; D005865:Gestational Age; D017052:Hospital Mortality; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D008297:Male; D008606:Mental Processes / Q000502:physiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D059285:Pregnancy, Twin / Q000706:statistics & numerical data*; D047928:Premature Birth / Q000453:epidemiology*
keywords: Epidemiology; Fetal Medicine; Neurodevelopment; Neurodisability; Twins