Traffic pollution is putting unborn babies' health at risk

Air pollution from road traffic is having a detrimental impact upon babies' health before they are born, new research reveals.

The findings published in the BMJ suggest exposure to traffic pollution during pregnancy is linked to low birth weight, with London a main area of ‘concern’.

A team of researchers, led by Imperial College London, say their findings are applicable to other UK and European cities and call for environmental health policies to improve air quality in urban areas.

Authors Sarah Stock and Tom Clemens, said: “Our findings suggest that air pollution from road traffic in London is adversely affecting fetal growth.

“With the annual number of births projected to continue increasing, the absolute health burden will increase at the population level, unless air quality improves.”

A team led by Imperial College London used national birth registers to study more than 540,000 births in Greater London between 2006 and 2010.

Researchers estimated average monthly concentrations of traffic-related pollutants by looking at the mother’s home address at the time of birth.

Analysis of the data found that increases in traffic-related air pollutants were associated with two per cent to six per cent increased odds of low birth weight and one per cent to three per cent increased odds of being small for gestational age.

The study found no evidence that exposure to road traffic noise was linked to birth weight, but the authors said they “cannot rule out that an association might be observed in a study area with a wider range of noise exposures”.

Reducing London's annual average pollution concentration by 10 per cent has been estimated to prevent around 90 babies being born at term with low birth weight each year.

Previous studies have linked a low birth weight (weighing less than five pounds, eight ounces) to future ill health, with a low weight inversely correlated with cardiovascular and metabolic diseases.

Ms Stock and Mr Clemens added: “The study should increase awareness that prenatal exposure to small particle air pollution is detrimental to the unborn child. However, increasing awareness without solutions for risk reduction may serve only to increase maternal anxiety and guilt.

“The challenge is to maintain reductions in the longer term through combinations of national and local authority action, particularly around reducing congestion and implementing interventions to tackle diesel combustion emissions in urban areas.”