Cerebral palsy in eastern Denmark: Declining birth prevalence but increasing numbers of unilateral cerebral palsy in birth year period 1986–1998

The Cerebral Palsy Registry in eastern Denmark has been collecting cases using a uniform data sampling procedure since birth year 1979. Children are included by two child neurologists and an obstetrician. Information on pregnancy, birth, neonatal period, impairments and demographic data are registered.The total cerebral palsy birth prevalence has been significantly decreasing since the birth period 1983–1986 with 3.0 per 1000 live births until the period 1995–1998 with 2.1 per 1000 live births. The overall decrease was seen in preterm infants (<31 weeks) as well as in term infants and despite a simultaneous fall in perinatal and early neonatal mortality in the preterm group.Analysing the subtypes of CP we found a significant increase in the numbers as well as the rate of unilateral CP with a simultaneous fall in the numbers as well as the rate of bilateral CP. The explanation of this rise is not obvious. A change from bilateral periventricular lesions to unilateral is a possibility, but no major change in the neonatal handling could be documented.Regarding associated impairments, developmental delay/learning disabilities as well as motor function assessed by ability to walk (unassisted/assisted), both have changed toward higher percentage of children with unassisted walking and in need of special education.