Estimating the health‐care costs of children born to pregnant smokers in England: cohort study using primary and secondary health‐care data

BACKGROUND AND AIMS: Little is known about the long‐term economic consequences of smoking during pregnancy. We estimated the association between smoking in pregnancy and the costs of delivering health‐care to infants and children in England, and investigated which aspects of care are the key drivers of these costs. METHODS: We used Hospital Episode Statistics (HES) linked with Clinical Practice Research Datalink (CPRD) data in England from January 2003 to January 2015 in children with longitudinal data for at least 1, 5 and 10 years after birth. Poisson regression provided rate ratios (RR) and 95% confidence intervals (CIs) comparing health‐care episode rates between those exposed and not exposed to smoking during pregnancy. Linear regression was used to compare estimated costs between groups (£ sterling, 2015 prices) and generalized linear multivariable (GLM) models adjusted for potentially moderating factors. RESULTS: A total of 93 152 singleton pregnancies with the required data were identified. Maternal smoking in pregnancy was associated with higher primary care, prescription and hospital in‐patient episode rates, but lower out‐patient visit and diagnostic test rates. Adjusting for year of birth, socio‐economic deprivation, parity, sex of child and delivery method showed that maternal smoking in pregnancy was associated with increased child health‐care costs at 1 year [average cost difference for children of smokers, β = £91.18, 95% confidence interval (CI) = £47.52–134.83 and 5 years of age (β = £221.80, 95% CI = £17.78–425.83], but not at 10 years of age (β = £365.94, 95% CI = –£192.72 to £924.60). CONCLUSION: In England, maternal smoking in pregnancy is associated with increased child health‐care costs over the first 5 years of life; these costs are driven primarily by greater hospital in‐patient care.