SAN DIEGO — The development of cerebral palsy is associated with adverse intrapartum events in about 27% of term infants and 38% of preterm infants with the condition, according to findings from a large, retrospective population-based cohort analysis.
Previous studies have indicated that intrapartum events were a factor in only 10% of infants with cerebral palsy. “Our data would suggest that 10% estimate is a little bit low,” Dr. William M. Gilbert said in an interview during a poster session at the annual meeting of the Society for Maternal-Fetal Medicine.
For the study, which is the largest of its kind, Dr. Gilbert and his associates analyzed maternal/infant discharge and birth records in California for 1991–2001.
Of the more than 6,000,000 births that occurred over the 10-year period, 8,946 children with cerebral palsy were identified. Of these, 5,478 were delivered at term and 3,468 were delivered preterm. All cases of cerebral palsy were then compared with the population without cerebral palsy, said Dr. Gilbert, codirector of the Center for Perinatal Medicine and Law at the University of California, Davis.
Adverse obstetrical outcomes included asphyxia, placental abruption, fetal distress, and uterine rupture. Adverse neonatal outcomes included mild to severe birth asphyxia, respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, and meningitis.
The investigators reported that 38% of preterm infants and 27% of term infants with cerebral palsy had one or more of the adverse obstetrical outcomes, compared with 17% and 13% of controls, respectively. These differences are statistically significant.
Maternal or neonatal infections only modestly affected the risk of cerebral palsy in term infants (9% with cerebral palsy vs. 6% among controls), while the impact was significantly greater in preterm infants (29% with cerebral palsy vs. 11% among controls).
Adverse neonatal outcomes occurred significantly more often in infants with cerebral palsy, compared with controls—5% among term infants vs. 0.5% among controls and 59% among preterm infants vs. 6% among controls.
“Birth asphyxia increased the risk of cerebral palsy development in term infants (eightfold) more than in the preterm infants (twofold), possibly suggesting that term infants cannot handle asphyxiating insults as well as preterm infants,” Dr. Gilbert and his associates said.
Dr. Gilbert had no conflicts of interest to disclose.