Smoking during pregnancy affects children's coordination and physical control

23 September 2010

Women who smoke during pregnancy run the risk of adversely affecting their children's co-ordination and physical control, according to a Swedish study using NCDS data.

Women who smoke during pregnancy run the risk of adversely affecting their children's co-ordination and physical control, according to a Swedish study using NCDS data.

Boys' abilities may be affected to a greater extent than those of girls, as there is a link between nicotine and testosterone, says an article by researchers at Örebro University that was published this month by the Journal of Epidemiology and Community Health.

Matz Larsson and Professor Scott Montgomery, a former member of the CLS team in London who is now based in Sweden, explain that nicotine, which can influence brain development, interacts with testosterone, particularly during the foetal stage. This could make boys especially susceptible to foetal nicotine exposure.

The physical control and co-ordination of members of the 1958 NCDS cohort were tested at age 11 by a school doctor. The children were timed to see how long it took them to pick up 20 matches, using their left and their right hands. They were also asked to tick up to 200 squares, again using their left and right hands, and then had to copy a simple figure or shape using their dominant hand.

The children with mothers who had smoked at least nine cigarettes a day during pregnancy had greater difficulty completing the tests - especially when using their non-dominant hand, which for most of us is the left hand.

There may be several explanations, the researchers say. One is that the nicotine interacts with acetylcholine, which is an important neurotransmitter and messenger when the brain is developing during the foetal stage. But it might also be that the mother's smoking leads to a form of foetal malnutrition, says Matz Larsson.

His colleague, Scott Montgomery, adds: “We believe this is an interesting study as it is based on physical rather than cognitive tests, which are dependent on, for example, elements of learning. That makes our results less sensitive to the influence of social and economic factors. Other factors linked to the mother's smoking may still have affected the result, but the difference in motor abilities remained even after a check for such factors.”

These findings could also help to explain why neurological function in childhood is linked with adverse health outcomes in later life, such as obesity and Type 2 diabetes, as these are also associated with maternal smoking during pregnancy. Even a slight impairment in childhood can be linked to a more rapid decline in motor function and health later in life, Montgomery says.

Subscribers to the Journal of Epidemiology and Community Health can find the full article here.