title: Neurodevelopmental outcomes of preterm singletons, twins and higher-order gestations: a population-based cohort study.
abstract: OBJECTIVE
  To study the neurodevelopmental outcomes of multiple (twins, triplets, quads) compared with singleton extremely preterm infants <29 weeks gestation.
  
  
  METHODS
  Population-based retrospective cohort study.
  
  
  METHODS
  A network of 10 neonatal intensive care units in a geographically defined area of New South Wales and the Australian Capital territory.
  
  
  METHODS
  1473 infants <29 weeks gestation born between 1 January 1998 and 31 December 2004.
  
  
  METHODS
  At 2-3 years of corrected age, a neurodevelopmental assessment was conducted using either the Griffiths Mental Developmental Scales or the Bayley Scales of Infant Development II.
  
  
  METHODS
  Moderate-severe functional disability was defined as developmental delay (Griffiths Mental Developmental Scales General Quotient or Bayley Scales of Infant Development-II Mental Development Index >2 SDs below the mean), moderate cerebral palsy (unable to walk without aids), sensorineural or conductive deafness (requiring amplification) or bilateral blindness (visual acuity <6/60 in the better eye).
  
  
  RESULTS
  Of the 1081 singletons and 392 multiples followed-up, singletons demonstrated higher rates of systemic infections, steroid treatment for chronic lung disease and birth weight <10th percentile. Moderate-severe functional disability did not differ significantly between singletons and multiples (15.8% vs 17.6%, OR 1.14; 95% CI 0.84 to 1.54; p=0.464). Further subgroup analysis of twins, higher-order gestations, 1st-born multiples, 2nd or higher-born multiples, same and unlike gender multiples, did not demonstrate statistically higher rates of functional disability compared with singletons.
  
  
  CONCLUSIONS
  Premature infants from multiple gestation pregnancies appear to have comparable neurodevelopmental outcomes to singletons.
authors.affiliation: Department of Medicine, Canberra Hospital, Garran, Australian Capital Territory, Australia.
authors.forename: Lokiny
authors.initials: L
authors.lastname: Gnanendran
authors.affiliation: Neonatal Intensive Care Units' Data Collection, NSW Pregnancy and Newborn Services Network, New South Wales, Australia.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bajuk
authors.affiliation: Department of Newborn Care, Royal Hospital for Women, New South Wales, Australia School of Women's and Children's Health, University of New South Wales, New South Wales, Australia.
authors.forename: Julee
authors.initials: J
authors.lastname: Oei
authors.affiliation: Department of Newborn Care, Royal Hospital for Women, New South Wales, Australia School of Women's and Children's Health, University of New South Wales, New South Wales, Australia.
authors.forename: Kei
authors.initials: K
authors.lastname: Lui
authors.affiliation: Department of Neonatology, Centenary Hospital for Women and Children, Garran, Australian Capital Territory, Australia School of Clinical Medicine, Australian National University, Australian Capital Territory, Australia.
authors.forename: Mohamed E
authors.identifier: http://orcid.org/0000-0003-4306-2933
authors.initials: ME
authors.lastname: Abdel-Latif
mesh_terms: D000886:Anthropometry / Q000379:methods; D020958:Australian Capital Territory / Q000453:epidemiology; D002657:Child Development / Q000502:physiology*; D015331:Cohort Studies; D002658:Developmental Disabilities / Q000453:epidemiology*; D004200:Diseases in Twins / Q000453:epidemiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007234:Infant, Premature / Q000523:psychology*; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D011379:Prognosis; D012189:Retrospective Studies; D014427:Twins / Q000523:psychology* / Q000706:statistics & numerical data