Risk factors for neonatal seizures: a population-based study, Harris County, Texas, 1992-1994

Risk factors for neonatal seizures were evaluated in 116,048 infants born between 1992 and 1994 to residents of Harris County, Texas; 207 of these infants were diagnosed with clinical neonatal seizures. Information was obtained from the infant's birth certificate to assess the relation between seizures and birth weight, gender, ethnicity, place of birth, mother's age, method of delivery, parity, and multiple births. These factors were evaluated by univariate and multivariate analysis using logistic regression. For preterm infants, a birth weight of <1,500 g was the strongest risk factor (relative risk (RR) = 9.1, 95% confidence interval (CI): 4.7, 17.5), followed by birth in a private/university hospital (RR = 2.8, 95% CI: 1.5, 5.0) and male gender (RR = 1.8, 95% CI: 1.0, 3.4). For term infants, significant risk factors included birth by cesarean section (RR = 2.2, 95% CI: 1.5, 3.2), small birth weight for gestational age (RR = 1.9, 95% CI: 1.2, 2.9), birth in a private/university hospital (RR = 1.8, 95% CI: 1.1, 3.0), and maternal age of 18-24 compared with 25-29 years (RR = 1.6, 95% CI: 1.1, 2.3). Birth by assisted vaginal delivery and primiparity were marginally significant for term infants. Birth weight is a significant risk factor for neonatal seizures. The role of perinatal complications warrants further evaluation.