Babies born to smoking mums 'have smaller brains

Children whose mothers smoked in pregnancy are more likely to become moody and depressed than other boys and girls, say scientists.

A study of more than 200 children found that those whose mothers were regular cigarette users while they were in the womb had smaller brains and were at greater risk of stress and anxiety.

Researchers suspect tobacco could affect development by destroying neurons and reducing oxygen to the foetus because of the narrowing of blood vessels.

The study, published in the journal Neuropsychopharmacology, said smoking throughout pregnancy could have long-term effects on the mental health of young children.

In England and Wales, 17 per cent of women smoke during pregnancy - while, among under 20s, the figure is 45 per cent.

Although most will go on to have a healthy baby, smoking can cause considerable damage to the unborn child.

Exposure to cigarettes in the womb is believed to alter brain structure, but little is known about how the organ's development is affected or if the behavioural problems observed are controlled by these differences.