Women who smoke while pregnant risk having hyperactive preschoolers who can't pay attention, a large study from the UK hints.
Although previous studies have demonstrated significant risks for school-aged boys, this is the first time an association has been shown between smoking during pregnancy and problems for girls and for boys as young as three, the researchers point out.
Dr Kate E. Pickett, of the University of York, Hull-York Medical School and colleagues looked for ties between smoking in pregnancy and behaviour and attention problems in more than 13 000 three-year-old boys and girls in the UK Millennium Cohort Study.
How the study was done
As part of the study, a wide range of information was gathered including family economic status, education level of parents, ethnicity, parents' marital status, financial difficulties and maternal smoking, drinking or drug use.
Questions were also asked about the children to assess behaviour and hyperactivity-inattention problems such as how easily their child was distracted or if their child was prone to temper tantrums, fight with or bully other kids, argue with grownups, steal, lie, and/or cheat.
In all, nearly 10% of women reported smoking heavily (+10 cigarettes a day) throughout their pregnancy, 12.5% were light smokers (less than 10 cigarettes a day), and 12.4% tried to quit, the researchers note in a report published in the Journal of Epidemiology and Community Health.
Even though no ill-effects of even heavy maternal smoking during pregnancy were recorded for most boys (61.6%) and girls (71.7%), the risk of developing behaviour or attention problems increased with maternal prenatal smoking, the researchers found.
Effect different in girls
They also found that the effect of smoking during pregnancy was different in boys and girls. Boys exposed to cigarette smoke in the womb were more likely to have behaviour and attention deficit problems, while girls with this exposure were more likely to experience behaviour problems alone.
Girls whose mothers quit smoking during pregnancy had a lower risk of behaviour problems than girls whose mothers never smoked leading the researchers to conclude the mother's "the ability to quit" may be a characteristic of "restraint and easy temperament" that the daughters inherit.
Smoking throughout pregnancy carries the highest risk for both boys and girls, according to the data. "Overall, the most important factor seems to be smoking continuously throughout pregnancy, more than amount smoked," Pickett said.
"Persistent heavy smokers had a higher risk of having a boy with conduct problems than light smokers. For conduct problems in girls, any continuous smoking seemed to matter more than amount. Similarly, for hyperactivity-inattention problems both light and heavy smokers had similarly elevated risks compared to non-smokers," Pickett explained. – (Reuters Health, November 2009)
Smoking mom=psychotic kid