PREVALENCE OF PREMATURITY, LOW-BIRTH-WEIGHT, AND ASPHYXIA AS PERINATAL RISK-FACTORS IN A CURRENT POPULATION OF CHILDREN WITH CEREBRAL-PALSY

To test the hypothesis that increasing survival of infants at highest risk for long-term neurological sequelae has strengthened the associat ions between perinatal events and subsequent cerebral palsy (CP), we c ompared the prevalence rates for prematurity, low birthweight congenit al malformations, and perinatal asphyxia from a current population of children with CP with those reported nearly 30 years ago by the Nation al Collaborative Peri natal Project (NCPP, 1959-1966) of the National Institute of Neurologic and Communicative Disorders and Stroke, Althou gh we saw no differences in the proportion of children who were born p rematurely, we did find a significant shift in the birthweight and ges tational age distribution, with a nearly threefold greater prevalence of births less than 1501 g in our population (31.1% and 95% confidence interval [Cl] of 20.6 to 41.7% vs 9.1% and 95% Cl of 5.0 to 13.2%). N early half (43.5%) of these very low birthweight infants had evidence of brain injury (intraventricular hemorrhage), a diagnosis not commonl y recognized in the NCPP. On the other hand, birth asphyxia and congen ital malformations occurred no more frequently in our population than that reported earlier. Furthermore, the majority (60%) of full-term in fants who develop CP continue to be the products of normal pregnancies and have no perinatal events that may have caused their neurological impairment. The increasing prevalence of births less than 1501 g among children with CP may well reflect the improving survival of very smal l infants over the last 30 years. We suggest that the results of this and other studies indicate it is time to consider a population-based t racking program, similar to that of the NCPP, to define more clearly c hanges in the epidemiological aspects of CP and to understand better t he relationship between neurological sequelae and neonatal-perinatal e vents.