Average treatment effect of maternal prenatal tobacco smoking on offspring developmental vulnerability in early childhood

Abstract

BackgroundEarly childhood developmental vulnerability has been closely related to the predictors of relatively good health, social and educational outcomes later in adulthood. However, the impacts of prenatal tobacco exposure on childhood developmental vulnerability have been rarely examined. Further, a few of the studies that have investigated maternal prenatal tobacco smoking and child developmental vulnerability have reported mixed results and there are currently no published estimates derived from causal epidemiological methods. MethodsWe conducted a retrospective population-based cohort study on the association between maternal prenatal tobacco smoking and developmental vulnerability in children born in Western Australia (WA). De-identified individual-level maternal, infant and birth records were obtained from the Midwives Notification System (MNS), a statutory record of all births in WA. WA register for Developmental Anomalies (WARDA) were also obtained from the WA Data Linkage. Records on early childhood developmental vulnerability at the median age of 5 years were obtained from the Australian Early Development Census (AEDC). We used a doubly robust estimator to estimate the causal effects. ResultsComplete data were available for 64,558 mothers-children's pairs. Approximately 16% of children were exposed to maternal prenatal tobacco smoking. Children exposed to maternal prenatal tobacco smoking were more likely to be classified as developmentally vulnerable/at-risk on the physical health and wellbeing (RR = 1.40, 95%CI:1.36–1.45), social competence (RR = 1.42, 95%CI: 1.38–1.47), emotional maturity (RR = 1.34, 95%CI:1.30–1.39), language and cognitive skills (RR = 1.50, 95%CI:1.45–1.54), and communication skills and general knowledge (RR = 1.37, 95%CI:1.33–1.42) domains. ConclusionMaternal prenatal exposure to tobacco may influence early childhood developmental vulnerability. Early intervention to quit tobacco smoking before becoming pregnant could potentially reduce later childhood developmental vulnerability on multiple domains.