Effect of antenatal exposure to maternal smoking on behavioural problems and academic achievement in childhood: prospective evidence from a Dutch birth cohort.

Aim: To examine effects of maternal smoking during pregnancy on academic achievement and emotional and behavioural problems during childhood.

Methods: Least squares regression was used to examine associations between maternal smoking prior to delivery and subsequent academic performance and behaviour of 1186 children aged 5.5-11 years. Crude associations were adjusted for risk factors that were significantly related to the respective outcomes.

Main Outcome Measures: Parents and teachers were asked to indicate, on a 10-item questionnaire, whether they regarded the child as more, the same, or less shy/withdrawn (internalising), troublesome (externalising), and attention deficient than the average child. Reading, spelling, and arithmetic performance levels were assessed with short standardised Dutch tests.

Results: After adjustment for confounders like socio-economic status and pre- and perinatal complications, children of mothers who smoked during pregnancy showed more signs of attention deficit and displayed higher levels of troublesome (externalising) behaviour than non-cigarette-exposed children. Also, children of smoking mothers performed worse on arithmetic and spelling tasks. Spelling problems were more pronounced when the mother continued to smoke after the child's birth. Excessively withdrawn (internalising) behaviour was not related to maternal smoking but to factors like the mother's use of psychotropic drugs and bottle-instead of breastfeeding.

Conclusion: Perinatal antecedents of internalising behaviour on the one hand and externalising behaviour, attention deficit, and learning problems on the other seem to be distinct. Only the latter are independently associated with maternal smoking during pregnancy and thus potentially amenable to early preventive effort, for instance, through continued health education emphasising the health hazards of nicotine use by pregnant women.