Cerebral Palsy after Neonatal Encephalopathy: How Much Is Preventable?

To determine the expected proportion of term cerebral palsy (CP) after neonatal encephalopathy (NE) that could theoretically be prevented by hypothermia and elucidate the perinatal factors associated with CP after NE in those who do not meet currently used clinical criteria required to qualify for hypothermia ("cooling criteria").

Using the Canadian CP Registry, we categorized children born at ≥ 36 weeks with birth weight ≥ 1800 g with CP after moderate or severe NE according to the presence or absence of cooling criteria. Maternal, perinatal, postnatal, and placental factors were compared between the 2 groups. A number needed to treat of 8 (95% CI 6-17) to prevent one case of CP was used for calculations.

Among the 543 term-born children with CP, 155 (29%) had moderate or severe NE. Sixty-four of 155 (41%) met cooling criteria and 91 of 155 (59%) did not. Shoulder dystocia was more common in those who did not meet cooling criteria (OR 8.8; 95% CI 1.1-71.4). Low birth weights (20% of all singletons), small placentas (42%), and chorioamnionitis (13%) were common in both groups.

The majority of children with CP after NE did not meet cooling criteria. An estimated 5.1% (95% CI 2.4%-6.9%) of term CP after NE may be theoretically prevented with hypothermia. Considering shoulder dystocia as an additional criterion may help recognize more neonates who could potentially benefit from cooling. In all cases, a better understanding of the antenatal processes underlying NE is essential in reducing the burden of CP.