Childhood Respiratory Morbidity after Late Preterm and Early Term Delivery: a Study of Medicaid Patients in South Carolina

Background There is a growing body of research documenting an increased risk of neonatal morbidity for late preterm infants (LPI, 340/7 weeks to 366/7 weeks) and early term infants (ETI, 370/7 weeks to 386/7 weeks) compared with term infants (TI, 390/7 to 416/7); however, there has been little research on outcomes beyond the first year of life. In this study, we examined respiratory outcomes of LPI and ETI in early childhood. Methods South Carolina Medicaid claims data for maternal delivery and infant birth hospitalisations were linked to vital records data for the years 2000 through 2003. Medicaid claims for all infants were then followed until their fifth birthday or until a break in their eligibility. Infants born between 340/7 and 416/7 weeks were eligible. Infants with congenital anomaly, birthweight below 500 g or above 6000 g, and multiple births were excluded. We fit Cox proportional hazard models from which adjusted hazard ratio (HR) and 95% confidence interval (CI) were derived. Results A total of 3476 LPI, 12 398 ETI, and 25 975 term infants were included. Both LPI and ETI were associated with an increased risk for asthma (LPI: HR 1.24, 95% CI 1.10, 1.40; ETI: HR 1.12, 95% CI 1.06, 1.19), and bronchitis (LPI: HR 1.15, 95% CI 1.00, 1.34; ETI: HR 1.13, 95% CI 1.05, 1.2) at 3 to 5 years of age. Conclusions Late preterm infants and early term infants are at increased risk for asthma and bronchitis.