Children born to mothers who drank alcohol while pregnant may be more at risk of behavioural problems than other children, research shows.
Experts from Indiana University in Bloomington analysed the drinking habits of 4,912 mothers and their children's conduct between the ages of 4 and 11.
Every additional day that mothers drank alcohol while pregnant was linked to an increase in their unborn child's conduct problems.
Children whose mothers drank alcohol while pregnant also had more attention and impulsivity problems than children whose mothers did not drink.
"These results are consistent with prenatal alcohol exposure exerting an environmentally mediated causal effect on childhood conduct problems, but the relation between prenatal alcohol exposure and attention and impulsivity problems is more likely to be caused by other factors correlated with maternal drinking during pregnancy," say the study authors.
'These findings support a strong inference that prenatal alcohol exposure causes an increased risk of offspring conduct problems through environmental processes.
"Therefore, prevention efforts should continue to target alcohol consumption during pregnancy."