Background: Late preterm infants (34-37 weeks' gestation) are often perceived at similar risks for morbidity and mortality as term infants.
Objective: To compare the neurodevelopmental outcomes of late preterm to term infants.
Methods: Our study sample of 6300 term and 1200 late preterm infants came from the Early Childhood Longitudinal Study-Birth Cohort. We used general estimating equations to get weighted odds of having developmental delay, mental index scores (MDI) or psychomotor index scores (PDI) < 70, at 24 months of age.
Results: Late preterm infants compared with term infants had lower MDI (85 vs 89) and PDI (88 vs 92), both P < .0001, respectively. A higher proportion of late preterm infants compared with term infants had an MDI <70 (21% vs 16%; P < .0001). An equal number had PDIs <70 (6.1% vs 6.5%). After controlling for statistically significant and clinically relevant descriptive characteristics, late preterm infants still had higher odds of mental (odds ratio: 1.52 [95% confidence interval: 1.26-1.82] P < .0001) or physical (odds ratio: 1.56 [95% confidence interval: 1.30-1.89] P < .0001) developmental delay.
Conclusions: Late preterm infants have poorer neurodevelopmental outcomes than term infants and have increased odds to have a mental and/or physical developmental delay.