Epidemiology of spastic tetraplegic cerebral palsy in Sweden. II. Prevalence, birth data and origin.

The prevalence and origin of spastic tetraplegic cerebral palsy (TPL) was investigated in a population-based study from 15 Swedish counties and the city of Gothenburg. The series comprised 96 children and adolescents born in 1959-1978. The prevalence at the ages of 5-24 years was 8 per 100,000. The etiological analysis was based on the 91 TPL subjects, born in Sweden. The preterm rate was 7%. There were 46 males and 45 females. Excluding postnatal cases, the mean birth weight was 2949 g and the proportion of SGA 21%. An obvious prenatal origin was found in 21 (mainly microcephaly, other CNS maldevelopment, intrauterine CMV-infection), an obvious perinatal origin in nine (mainly cerebral hemorrhage), and an obvious postnatal origin in 16 (mainly CNS infection). A potential prenatal origin was considered in six, a combined pre- and perinatal in 15, a perinatal in 13 and in 11 the origin of TPL was untraceable. An optimality analysis showed that reduced optimality in the partum and postpartum periods discriminated between pre- and perinatal etiology of TPL. Cases with obvious perinatally derived TPL had a high load of complications in the partum and postpartum periods, whereas these periods had been fairly uncomplicated in cases with an obviously prenatal origin of TPL. - It was indicated that some 50-55% of TPL was prenatally, around 30% perinatally and some 15-20% postnatally derived. The low preterm rate as well as the proportion of perinatal brain damage in TPL cases has probably increased in recent birth year periods due to the appearance of very preterm, severely multi-impaired children in the CP panorama.