FOETUSES exposed to high levels of air pollution, such as traffic fumes, are significantly smaller and can have lower intelligence and more cardiovascular problems than babies in country areas, a world-first study has found.

Researchers in Brisbane studied ultrasound scans from more than 15,000 foetuses during a 10-year period and found that women living in postcodes with high levels of sulfur dioxide, nitrogen dioxide and particulate matter in the air had babies with shorter femur bones and smaller head and abdominal circumferences.

Nitrogen dioxide is usually produced by kerosene heaters, unvented gas stoves, heaters and passive smoking, while sulphur dioxide comes from diesel-powered vehicles and some industrial processes, such as fertiliser manufacturing, aluminium smelting and steel making. Particulate matter is found in car-exhaust fumes.

A senior research fellow at the Queensland University of Technology and co-author of the study, Adrian Barnett, said yesterday the research was the first of its kind to use ultrasound measurement as a direct estimate of growth, rather than birth weight as a delayed measure of growth.

He said only foetuses between 13 and 26 weeks gestation in women who lived within two kilometres of a pollution monitoring station were included in the study, published in the international journal Environmental Health Perspectives.

"When analysing scans from women at different distances to monitoring sites, we found that there was a negative relationship between pollutants such as sulphur dioxide found in diesel emissions, and ultrasound measurement," Dr Barnett said.

"If the pollution levels were high, the size of the foetus decreased significantly."


"Birth weight is a major predictor of later health; for example, bigger babies have been shown to have higher IQs in childhood and lower risk of cardiovascular disease in adulthood," he said.

"What happens when you're a foetus can have major implications for the rest of your life."

Dr Barnett said it was wise for pregnant women to reduce their exposure to air pollution by not walking along busy roads, not riding motor scooters or motorcycles and limiting the time spent waiting in traffic.

"On a practical level it can be difficult to reduce your exposure to air pollution, but the less exposure a pregnant woman has, the better off their baby will be."