Risk of Neonatal Neurologic Morbidity in Advancing Term Gestations.

ABSTRACT

OBJECTIVE: Placental insufficiency is associated with neonatal neurologic morbidity and late-term gestations (410/7-416/7 weeks). Whether late-term infants are at increased risk of neurologic morbidity compared with term infants (390/7-406/7 weeks) remains unclear. We aim to compare risk of neurologic morbidity among late-term and term infants. STUDY DESIGN: This secondary analysis of a single-institution prospective cohort study included all liveborn, nonanomalous singleton term and late-term infants, with data on adverse neonatal outcomes up until 28 days of life. The primary outcome was a neonatal neurologic morbidity composite, defined by having one of these conditions neonatal seizures, intraventricular hemorrhage, hypoxic-ischemic encephalopathy, and neonatal hypothermic therapy. Secondary outcomes were the composite's individual components and nonneurologic neonatal morbidity. Multivariable logistic regression adjusted for delivery mode, nulliparity, and labor type. RESULTS: Of 5,529 infants included, 747 were late term and 4,782 were term. The risk of composite neurologic morbidity was not significantly different among late-term or term infants (0.5 vs. 0.6%; adjusted odds ratio 0.59, 95% confidence interval 0.21-1.71). Overall neonatal morbidity was not significantly different in the two groups, though late-term infants had a nonsignificantly higher prevalence of respiratory distress syndrome (5.5 vs. 3.3%) and meconium aspiration syndrome (0.7 vs. 0.2%). CONCLUSION: Neonatal neurologic morbidity is uncommon after 39 weeks. Risk does not increase after 41 weeks.