title: Changes in the prevalence of cerebral palsy for children born very prematurely within a population-based program over 30 years.
abstract: BACKGROUND
  Although cerebral palsy (CP) among extremely premature infants has been reported as a major morbidity outcome, there are difficulties comparing published CP rates from many sites over various birth years.
  
  
  OBJECTIVE
  To assess the changes in population-based, gestational age-specific prevalence rates of CP among extremely premature infants over 30 years.
  
  
  METHODS
  Prospective population-based longitudinal outcome study.
  
  
  METHODS
  In Northern Alberta, 2318 infants 20 to 27 weeks' gestational age with birth weights of 500 to 1249 g were liveborn from 1974 through 2003. By 2 years of age, 1437 (62%) had died, 23 (1%) were lost to follow-up, and 858 (37%) had received multidisciplinary neurodevelopmental assessment.
  
  
  METHODS
  Population-based prevalence rates of CP were determined. Logistic regression with linear spline was used to assess changes in CP prevalence over time.
  
  
  RESULTS
  At age 2 years, 122 (14.2%) of 858 survivors had CP. This diagnosis was confirmed for each child by age 3 years or older. Among those whose gestational age was 20 to 25 weeks, population-based survival increased from 4% to 31% (P<.001), while CP prevalence per 1000 live births increased monotonically from 0 to 110 until the years 1992-1994 (P<.001) and decreased thereafter to 22 in the years 2001-2003 (P<.001). Among those whose gestational age was 26 to 27 weeks, population-based survival increased from 23% to between 75% and 80% (P<.001), while CP prevalence per 1000 live births increased monotonically from 15 to 155 until the years 1992-1994 (P<.001) and then decreased to 16 in the years 2001-2003 (P<.001). For all survivors born in the years 2001-2003, CP prevalence was 19 per 1000 live births.
  
  
  CONCLUSIONS
  Population-based CP prevalence rates for children whose gestational age was 20 to 27 weeks and whose birth weight ranged from 500 to 1249 g show steady reductions in the last decade with stable or reducing mortality, reversing trends prior to 1992-1994.
authors.affiliation: Section of Neurosciences, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada. charlene.robertson@capitalhealth.ca
authors.forename: Charlene M T
authors.initials: CM
authors.lastname: Robertson
authors.forename: Man-Joe
authors.initials: MJ
authors.lastname: Watt
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yasui
mesh_terms: D000416:Alberta / Q000453:epidemiology; D002547:Cerebral Palsy / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D016015:Logistic Models; D008137:Longitudinal Studies; D015995:Prevalence; D016019:Survival Analysis; D017741:Survivors / Q000706:statistics & numerical data*