Smoking 'can make babies badly behaved'

Pregnant women who smoke heavily risk having children who are badly behaved, a study into the effects of tobacco on the development of babies suggests.

The research found that children of mothers who smoked more than 20 cigarettes a day throughout their pregnancies were more likely to be disruptive and antisocial at primary school age.

Professor Terrie Moffitt of the Institute of Psychiatry, King's College London, said the findings could only be explained by smoking rather than other known risk factors for antisocial behaviour such as poverty, social class and low birth rate.

One theory was that there was something in cigarette smoke – perhaps nicotine – that affected the developmental genes involved in the growth or maturity of the foetal brain, she said.

The research, which has not yet been published in a peer-reviewed scientific journal, involved studying the school reports of more than 1,116 sets of identical and non-identical twins as well as interviews with their mothers.

Although smoking during pregnancy is known to be bad for the health of the foetus, this is the first study to suggest it might also cause behavioural problems.