Etiology of cerebral palsy

AIMS: To register the prevalence of cerebral palsy (CP) and determine etiological factors for the condition. METHODS: Population based study with registration of CP-cases in children born during the 30-year period 1970-99. Cases with postneonatal etiology were excluded. RESULTS: 166 CP-cases were registered among 70 824 children, a prevalence of 2.3 per 1000 live born infants. The prevalence did not change significantly during the period. 66 (40%) were low birthweight infants (LBWIs; or = 2500 g). The origin was classified as prenatal in 37 (22%), perinatal/neonatal in 78 (47%) and unclassifiable in 51 (31 %). In LBWIs 39/66 (59%) had a perinatal/neonatal etiology, most frequently intra- or periventricular hemorrhages (IVH/PVH) and/or periventricular leukomalacia (PVL) or cerebral infarctions (CI) (17; 44%). In NBWIs 39/100 (39%) had a perinatal etiology, most frequently hypoxic-ischemic encephalopathy (HIE) (31; 79%). CONCLUSIONS: In a substantial percentage of CP-cases perinatal/neonatal brain injury was classified as the cause. Among these IVH/PVH/PVL/CI dominated in LBWIs, while HIE dominated in NBWIs. Our data may point to preventability of a larger part of CP than earlier suggested.