Pollution may stunt babies' growth

The study, published in the international journal Environmental Health Perspectives, found that pregnant women who live in traffic-heavy suburbs are carrying smaller foetuses than those from "cleaner" areas.

The Brisbane researchers say their findings are the first to illustrate the effect of air pollution before birth, the most vital and vulnerable time of development.

"We already knew that air pollution leads to smaller babies, but we've been able to show these changes happen very early on, when the brain and organs are still developing," said Queensland University of Technology researcher Dr Adrian Barnett. "On the grounds of this, women should be thinking carefully about reducing their exposure if they're pregnant."

The study compared the foetus sizes of more than 15,000 ultrasound scans to air pollution levels in different postcodes within a 14-kilometre radius of downtown Brisbane.

"The study found that mothers with a higher exposure to air pollution had foetuses that were, on average, smaller in terms of abdominal circumference, head circumference and femur length," Dr Barnett said. "If the pollution levels were high the size of the foetus decreased significantly."

Dr Barnett said with research showing that bigger babies were healthier in childhood and adulthood, foetus size during pregnancy was important.

"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.

The researchers need to collect more data from individual mothers before they can be more certain about the effects of air pollution on foetal development. But in the meantime they warn it would be wise for mothers-to-be to try to reduce their exposure.