Long-term follow-up of term neonates with perinatal asphyxia

Available evidence shows adverse sequelae do not follow perinatal asphyxia unless encephalopathy is part of the neonatal clinical presentation. Where neonatal encephalopathy follows evidence of late fetal and/or early neonatal distress, the staging of the encephalopathy is useful for determination of prognosis; those with mild encephalopathy do well; those with severe encephalopathy do poorly. We believe this staging could be made more universally useful as an outcome variable for study of the etiology and timing of perinatal hypoxic-ischemic injury as well as for prediction of long-term outcome, if clinical correlates to pathophysiologic hypoxic-ischemic insults were used more broadly as the basis for defining the staging criteria. Most survivors of perinatal asphyxia do not have adverse sequelae, and later cognitive development has been shown to be similar to normative data. Although survivors of mild or severe encephalopathy have a predicted outcome, the outcome of those with moderate (Stage 2) hypoxic-ischemic encephalopathy is less certain; however, these children are at risk for neurologic disability and future academic failure. Prediction equations with good specificity for school-readiness outcome of the nondisabled survivors of moderate encephalopathy have been established allowing for early discharge from follow-up for those children predicted to do well. Mean school-age psychoeducational test results show nondisabled moderate encephalopathy survivors have scores below those in the mild encephalopathy group as well as below comparison groups, particularly for tests involving the auditory pathway, attention, and short-term recall; it is not known if these delays will resolve with time. School-aged nondisabled moderate encephalopathy survivors did not show the perceptual-motor delay reported in younger survivors. Overall, tests used to evaluate subtle changes that may relate to perinatal hypoxic-ischemic injury have been inadequate; future studies should include tests of acquisition of new learning, memory, problem solving, and reasoning. Further research is required to define the nature and timing of perinatal insults and the continued function of survivors.