Neonatal abstinence syndrome and early childhood morbidity and mortality in Washington state: a retrospective cohort study

OBJECTIVE: The objective of the study was to evaluate the association between neonatal abstinence syndrome (NAS) and long-term childhood morbidity and infant mortality. STUDY DESIGN: We conducted a cohort study of infants born in Washington State during 1990 to 2008 who were diagnosed with NAS (n = 1900) or were unexposed (n = 12,283, frequency matched by birth year). 5-year hospital readmissions and infant mortality were ascertained. RESULTS: Children with history of NAS had increased risk of readmission during the first 5 years of life relative to unexposed children; this remained statistically significant after adjustment for maternal age, maternal education, gestational age and intrapartum smoking status (readmission rates: NAS = 21.3%, unexposed = 12.7%, adjusted relative risk (aRR) 1.54, 95% confidence interval (CI) 1.37 to 1.73). NAS was associated with increased unadjusted infant mortality risk, but this did not persist after adjustment (aRR 1.94, 95% CI 0.99 to 3.80). CONCLUSION: The observed increased risk for childhood hospital readmission following NAS diagnosis argues for development of early childhood interventions to prevent morbidity.