PREGNANT women exposed to air pollution just before or after conceiving are at greater risk of their children being born with birth defects, according to a new study.

Although the increased risk is modest, researchers say the potential impact is worrying because all pregnant women have some amount of exposure to pollution.

They found that women exposed to air pollution just prior to conception or during the first month of pregnancy face an increased risk of their children being born with birth defects – such as a cleft lip or palate, or an abnormal heart.

Senior author Dr Emily DeFranco, of Cincinnati Children’s Hospital Medical Centre, said: “The most susceptible time of exposure appears to be the one month before and after conception.

“Public health efforts should continue to highlight the importance of minimising population-level exposure to harmful particulate matter in the air.”

Dr DeFranco and her colleagues examined fine particulate matter, which is a significant health hazard because the tiny particles can deposit deep into the lower airways and air sacs within the lungs and enter the circulatory system.

Fine particulate matter is a mixture of extremely small particles and liquid droplets that get into the air and, once inhaled, can negatively affect many aspects of a person’s health.

Dr DeFranco says there are limitations to observational studies, but it still provides a good foundation on which future studies can build.