Epidemiology of cerebral palsy in Southern Denmark.

INTRODUCTION: The aim of this study was to describe the prevalence, subtypes, severity and neuroimaging findings of cerebral palsy (CP) in a cohort of children born in Southern Denmark. Risk factors were analysed and aetiology considered. METHODS: A population-based cohort study covering 17,580 live births from 2003 to 2008. RESULTS: The study included 43 children diagnosed with CP. The overall prevalence of CP was 2.4 per 1,000 live births (95% confidence interval (CI): 1.8-3.2). The gestational age (GA)-specific prevalence ranged from 63.5 per 1,000 live births for GA < 32 weeks to 1.3 for GA >= 37 weeks. Almost half of the children were born preterm and 28% were from multiple pregnancies. The prevalence of CP was 1.8 per 1,000 in singletons and 15.4 per 1,000 in multiples. Low GA and birth weight were risk factors for CP, also after stratification for multiple births. Spastic CP was the predominating subtype of CP, and 24 children (56%) were able to walk independently. White-matter lesions were the most common magnetic resonance imaging finding, and the aetiology of CP was known in 37% of cases. CONCLUSION: The overall prevalence of CP was slightly higher than that found in other Scandinavian studies due to its higher prevalence in the preterm group. Possible explanations include the high rate of multiple births in the background population. Neuroimaging findings were abnormal in the majority of children with CP, but aetiology could only be established in one third of the children. Primary prevention of CP is possible if the numbers of preterm births and multiple pregnancies can be reduced.