Abstract
It is estimated that the prevalence of nongenetic SMR associated with cerebral palsy has risen from 0.7 to about 0.9 per 1000 live births in the last decade. This is due to the predicted rise in total cerebral palsy prevalence to 2.5/1000 live births. This predicted prevalence of cerebral palsy is similar to that given for Western Australia in 1979-82, allowing for postnatal causes, but is higher than prevalence data from England and Sweden for that period. The estimated rise is due largely to improved survival and increased proportion of low birthweight babies since 1983 and also reflects the use of prevalence rates based on Mersey data. Improvements in prenatal diagnosis, and a parental choice of selective termination may lead to reductions in other causes of SMR, such as Down's syndrome and neural tube defects, so it seems that children both physically and mentally handicapped due to brain damage will contribute a greater proportion of the SMR population. The careload of these children is greater than that associated with many other causes of SMR and most survive into adult life. The implications for planning future services will need to be recognised.