Objective: To identify prenatal and perinatal characteristics associated with cerebral palsy (CP) in infants born weighing < 1500 gm (very low birth weight, VLBW).
Design: All 42 VLBW singleton infants with CP born in the period from 1983 to 1985 in a defined population were compared with 75 randomly selected VLBW control infants.
Results: Birth in a level I facility was associated with increased risk of CP (odds ratio (OR) 6.3, 95% confidence interval (CI) 1.8, 19), as was birth within 3 hours of the mother's first admission for delivery (OR 3.2, CI 1.4, 7.4). Delivery occurred within 3 hours of admission to a level I facilty in 24% of VLBW children with CP and no control children (OR (0.5 added to each cell of 2 x 2 table) 49, CI 3.1, 204). Chorionitis was associated with increased risk in children born more than 5 hours after admission (OR 4.3, CI 1.1, 13). Chorionitis followed by neonatal seizures occurred in 14% of VLBW children with CP (in 25% with spastic diplegia) and in no control child (OR (0.5 added to each cell of 2 x 2 table) 26, CI 1.6, 116). Preeclampsia was associated with decreased risk (OR 0.08, CI 0.02, 0.67), as was use of magnesium sulfate (OR 0.14, CI 0.05, 0.51) administered for preeclampsia or preterm labor. Other risk factors for CP included gravidity greater than one (OR 3.9, CI 1.2, 11), short interbirth interval (OR 4.1, CI 1.3, 12), and vaginal bleeding on the day of admission (OR 2.9, CI 1.2, 7.4).
Conclusions: In this population-based study, almost one fourth of the CP in VLBW children occurred in infants delivered in level I facilities soon after their mothers' admissions. Another 14% was in children who had neonatal seizures after birth to women with chorionitis. No control subject experienced either of these sequences.