A major European study involving thousands of Bradford mums has found that exposure during pregnancy to common air pollutants and traffic can significantly increase the risk of women having low-birthweight babies.

The study recently published in The Lancet Respiratory Medicine says its findings are a wake-up call to policy makers to reduce pollution and make ‘urban’ air safer and cleaner because of the risks.

Speaking about the study, Professor John Wright, from the Bradford Institute for Health Research, said: “Eleven thousand women from the Born in Bradford study were involved in this major research programme.

“Their participation has helped us to clearly demonstrate the major public health harm of air pollution in pregnancy.

“Unlike risk factors such as diet and smoking, air pollution is an exposure that we cannot reduce through individual actions. Our research provides a wake-up call to policy makers to improve the quality of the air we all share.

“There is an urgency to adopt more radical approaches, such as greener transport, to ensure we breathe safe, clean air.”

He said the study’s findings suggested a substantial proportion of cases of full-term babies with low birthweights could be prevented in Europe if urban air pollution was reduced.

Data for the study was co-ordinated by researchers in Spain and France from 14 studies in 12 European countries involving over 74,000 women who had single babies between February 1994 and June 2011.

Exposure to low levels of air pollution during pregnancy has also been linked with respiratory problems in childhood, as well as other diseases later in life.

Prof Wright said: “The widespread exposure of pregnant women worldwide to urban ambient air pollution at similar or even higher concentrations than those assessed in our study provides a clear message to policy makers to improve the quality of the air we all share.”

He also said by making the study’s findings public, it could help put pressure on policy makers to reduce air pollution.

The researchers estimate that for every increase of five micrograms per cubic metre in exposure to fine particulate matter during pregnancy – found in for example traffic fumes and industrial air pollutants – the risk of low birthweight at term rises by 18 per cent Importantly, this increased risk persists at levels below the existing EU annual air quality limit of 25 micrograms per cubic metre the study found.