title: Prevalence of cerebral palsy in twins, triplets and quadruplets.
abstract: BACKGROUND
  Twins and triplets are at higher risk of cerebral palsy than singletons. This study investigated the degree of risk for cerebral palsy in twins, triplets and quadruplets, and identified factors associated with the increased risk.
  
  
  METHODS
  The subjects were recruited from the Kinki University Twin and Higher Order Multiple Births Registry.
  
  
  RESULTS
  The subjects were 705 twins pairs (1410 twins), 96 sets of triplets (287 triplets excluding one infant death), and 7 sets of quadruplets (27 quadruplets excluding one infant death), who were born after 1977. The prevalence of cerebral palsy was 0.9% among 1410 twins, 3.1% among 287 triplets, and 11.1% among 27 quadruplets. Furthermore, the risks of producing at least one child with cerebral palsy were 1.5%, 8.0%, 42.9% in twin, triplet, quadruplet pregnancies, respectively. After adjusting for each associated factor using logistic regression, the risk of cerebral palsy was significantly associated with decrease in gestational age and asphyxia. The odds ratio indicated that infants whose gestational age was < 32 weeks were 20 times more likely to develop cerebral palsy than infants whose gestational age was > or = 36 weeks.
  
  
  CONCLUSIONS
  The prevalence of cerebral palsy in triplets and quadruplets was higher than that in twins. Lower gestational age was associated with a greater risk of cerebral palsy.
authors.affiliation: Department of Public Health, Kinki University School of Medicine, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Hayakawa
mesh_terms: D001238:Asphyxia Neonatorum / Q000150:complications / Q000453:epidemiology; D002547:Cerebral Palsy / Q000453:epidemiology*; D016009:Chi-Square Distribution; D002675:Child, Preschool; D036861:Delivery, Obstetric / Q000379:methods; D004200:Diseases in Twins / Q000453:epidemiology*; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000453:epidemiology; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008370:Manuals as Topic; D008423:Maternal Age; D011247:Pregnancy; D015995:Prevalence; D011783:Quadruplets / Q000706:statistics & numerical data; D012307:Risk Factors; D014310:Triplets / Q000706:statistics & numerical data