Risk Factors for Cerebral Palsy

Abstract

The purpose of this study was to investigate the relation between a series of maternal, antenatal, perinatal, socioeconomic and environmental variables and the occurrence of cerebral palsy (CP) in a setting different from those in which previous analytic epidemiologic studies had been undertaken. The study was of case-control design and included 103 children with cerebral palsy born between 1984 and 1988 and residents of the Greater Athens area at any time during 1991 and 1992. Controls were chosen among the neighbors of the index case or were healthy siblings of children with neurological diseases other than CP seen by the same neurologists as the children with CP; a total of 254 control children were eventually included. Statistical analysis was done by modeling the data through unconditional logistic regression. Statistically significant (p,<0.05) risk factors of potential causal importance were: twin membership (OR=10.2), gestational age (OR = 0.5 per 4 weeks), birth weight conditional on gestational age (OR = 0.9 per 100 g), congenital malformations (OR=7.5), unhealthy placenta (OR = 6.6), placenta previa (6 cases, no controls), abnormal amniotic fluid (OR = 3.6), head circumference more than 36 cm (OR = 9.0), general anesthesia during labor (OR = 4.3), forceps delivery (OR = 6.8), and birth trauma (OR = 11.5). Among children with no identifiable prenatal risk factors there was no excess prevalence of one or more perinatal risk factors in CP cases compared to controls, which implies that the latter factors impart their effect through interactions with co-existing prenatal or other risk factors.