Alterations in Neurobehavior at Term Reflect Differing Perinatal Exposures in Very Preterm Infants

Abstract

OBJECTIVES. Preterm infants have higher rates of cognitive and behavioral difficulties at school age than their term-born peers. We hypothesized that neurobehavior at term would be different in very preterm infants compared with term infants and that perinatal exposures would be associated with these alterations in neurobehavior. PATIENTS AND METHODS. Two standardized neurobehavioral evaluations were completed on 207 infants at term equivalent, including 168 very preterm infants (<1250 g or <30 weeks' gestation) and 39 term control infants. The assessments used were the Neonatal Intensive Care Unit Network Neurobehavioral Scale and the revised Hammersmith Neonatal Neurologic Examination. The relationship of perinatal variables to preterm infant neurobehavioral scores for both evaluations was examined. RESULTS. Compared with term-born infants, preterm infant neurobehavior was significantly altered for the Hammersmith Neonatal Neurologic Examination total score and all of the subtotals. Similarly, preterm infants displayed altered neurobehavior for the majority of the Neonatal Intensive Care Unit Network Neurobehavioral Scale summary scores. Complete perinatal data were available for 157 of 168 very preterm infants. The perinatal variables most strongly associated with altered preterm infant neurobehavior on multivariate regression analysis included the total number of days of assisted ventilation, intraventricular hemorrhage, and necrotizing enterocolitis. Positive perinatal influences on neurobehavioral performance at term on multivariate analysis included maternal antenatal steroids, female gender, and infants receiving breast milk at discharge home. CONCLUSIONS. Preterm infants at term equivalent showed alterations in motor behavior and higher cortically integrated functions. The pattern of abnormality in neurobehavior differed in relation to perinatal exposures. Neurobehavioral examination at term equivalent age is useful in evaluating the impact of neonatal intensive care.