Background: Preterm delivery is associated with an increased risk of cerebral palsy (CP). The greatest risk is for infants born <28 weeks' gestation.
Aims: To identify significant neonatal risk factors for CP and explore the interactions between antenatal and neonatal risk factors, among extremely preterm infants of 27 weeks' gestation or less.
Study design: Nested case control design.
Methods: Infants born between 1989 and 1996, at 24-27 weeks' gestation, were evaluated: 30 with CP at 2 years corrected age and 120 control infants matched for gestation age. Neonatal variables were compared using matched analyses with the interaction between antenatal and neonatal factors being examined using logistic regression analyses.
Results: Risk factors for CP on matched analyses included patent ductus arteriosus requiring surgical ligation, peri-intraventricular haemorrhage, moderate to severe ventricular dilatation, periventricular leukomalacia (PVL) and need for home oxygen. Independent neonatal predictors were ventricular dilatation (OR 7.3; 95% CI 1.6, 32.3), PVL (OR 29.8; 95% CI 5.6, 159.1) and home oxygen use (OR 3.4; 95% CI 1.2, 9.4). No interaction terms in the logistic models were significant between the previously identified pregnancy risk factors of absence of antenatal steroids and intrauterine growth restriction and the neonatal risk factors.
Conclusions: PVL is the most powerful independent predictor of CP in extremely preterm infants of 27 weeks' gestation or less and appears to be uninfluenced by antenatal factors.