A new study has revealed that pregnant women exposed to even low levels of air pollution are at a higher risk of delivering low birth weight babies.

The study, drawn from data on 74,000 pregnant women in 12 European countries gathered between 1994 and 2011, showed that air pollutants increases the risk of low birth weight and reduces average head circumference of babies born at term.

The study led by Centre for Research in Environmental Epidemiology in Barcelona found that for every increase of five micrograms per cubic metre in exposure to fine particulate matter during pregnancy, the risk of low birth weight in the baby rose by 18 percent.

Lead author Dr Marie Pedersen and his team estimated that if levels of fine particulates were reduced to 10 micrograms per cubic metre, 22 percent of cases of low birth weight among term deliveries could be prevented.

The study is published in the Lancet Respiratory Medicine.