A new British study suggests that air pollution triggered by traffic is linked to lower birth weight in babies. Previous studies have tied road traffic air pollution to low birth weight. Road traffic produces noise as well as pollution, but studies of noise pollution have had conflicting results, said the authors. Study leader Dr. Rachel Smith at the School of Public Health of the Imperial College in London told Reuters Health: “We know that noise is associated with adverse health effects, like sleep disruption, increased blood pressure, and cardiovascular disease, so it could plausibly have an impact on mothers’ health in pregnancy and the health of unborn babies.” Smith’s team wanted to investigate the effect of exposures to both traffic-related air and noise pollution during pregnancy on babies’ birth weight. “We found increased risk of babies being born with low birth weight or small for gestational age, at term, to mothers with higher exposure to air pollution from road traffic during pregnancy. We did not see an independent effect of road traffic noise on birth weight,” she added. The study was published in the British Medical Journal. Mothers’ home addresses at the time of birth were used to estimate the average monthly exposure to traffic-related pollutants including nitrogen dioxide, nitrogen oxides, and fine particulate matter, or PM2.5. The researchers also estimated average day and night-time road traffic noise levels. Increases in traffic-related air pollutants, especially PM2.5, were associated with 2-6% increased odds of having a low birth weight baby and about 1-3% increased odds of a baby being small for gestational age, even after taking road traffic noise into account. Sarah Stock, a researcher at the University of Edinburgh Queen’s Medical Research Institute in Edinburgh, UK, who was not involved in the study said it was known that air pollution from traffic is well known to be detrimental to child and adult health, but, this study provides further evidence that air pollution from traffic is also harmful to unborn babies.