The relationships between neonatal encephalopathy and cerebral palsy: a cohort study.

There is a high risk of cerebral palsy (CP) following neonatal encephalopathy (NE) with fits, often attributed to intrapartum asphyxia. The evidence for the association is inconclusive and antepartum factors offer an alternative explanation. A cohort study was carried out to assess the evidence for and against hypoxic ischaemic injury as the cause of NE-associated CP in term infants. A total of 57 159 consecutive births were enrolled. There were 150 cases with NE, of whom 92 had at least one fit and 58 had no fits. The incidence of all NE was 2.62 per 1000 births and of NE with fits was 1.61 per 1000 births. Infants with NE were followed-up to identify those with cerebral palsy. There were 13 cases of four-limb cerebral palsy and three with hemiplegia among the survivors. In 12 of the 13 cases of four-limb CP, a combination of low Apgar scores, an early onset acute evolving encephalopathy, acidosis, renal dysfunction and the absence of antepartum factors suggested an acute intrapartum event as the immediate cause of the NE. An obstetric event likely to cause acute hypoxic injury was identified in four of the 12 cases. The clinical picture was similar in the four with and the eight without a specific obstetric event. The pathway leading to NE-associated CP remains unexplained, but intrapartum events appear to play a major role in most cases.