Language Outcomes in Late Preterm Infants: A Population-based Birth Cohort Study
Published on: 2018-12-03
Background: Growing evidence suggests late preterm birth (34 to 36 6/7 weeks gestational age) poses risk for neurodevelopmental deficit. Associations between late prematurity and language impairment (LI) are poorly understood. We hypothesized that late preterm infants are at higher risk for LI compared to term infants. Methods: Late preterm infants were matched 1:1 with term infants from a population based birth cohort. Matching criteria included gender, date of birth, maternal age and education level. Speech, language, and cognitive standardized test scores were abstracted from school and medical records. Operationalized research criteria were developed to define LI. Associations between infant and parental characteristics and LI incidence were evaluated with Cox proportional hazards models. Results: The population-based birth cohort included 11,136 infants born 1994-2000.Following exclusions, 717 matched pairs of late preterm and term infants were available for comparison. LI incidence was 2.8 times higher in the late preterm infants (hazard ratio 2.79, 95% CI 1.24-6.30, p=0.01). Lower maternal and paternal education levels (p<0.02) were positively correlated with LI incidence after late preterm birth. Among late preterm infants, 42% (n=300) required NICU admission. NICU admission was not associated with a higher incidence of LI (HR 1.29, 95% CI 0.55-3.04, p=0.56). Conclusions: Late preterm infants have a higher incidence of LI compared to term infants matched on gender, date of birth, maternal age and education level. These findings warrant close monitoring of language development in late preterm infants to optimize early detection and intervention for those with signs of delay.