Traffic pollution putting unborn babies' health at risk, warn experts

December 5, 2017
traffic
Credit: Scott Meltzer/public domain

Air pollution from road traffic is having a detrimental impact upon babies' health in London, before they are born, finds a study published by The BMJ today.

The findings suggest that exposure to air from in London during pregnancy is associated with an increased risk of low weight babies born at full term. But traffic related noise seems to have no effect.

The researchers say their findings are applicable to other UK and European cities and call for environmental health policies to improve in urban areas.

Previous studies have shown associations between air pollution, pregnancy complications and childhood illness, but studies of in pregnancy have provided conflicting results.

So a team of London-based researchers led by Imperial College London set out to investigate the relation between exposure to both air and noise pollution from road traffic during pregnancy and two birth weight outcomes - low birth weight (less than 2500 g) and being born small for .

Using national birth registers, they identified over 540,000 live, single, full-term births occurring in the Greater London area between 2006 and 2010.

Mother's home address at time of birth was recorded and average monthly concentrations of traffic related pollutants - nitrogen dioxide (NO2), nitrogen oxides (NOx), and fine particulate matter (PM2.5) from traffic exhaust and non-exhaust sources, such as brakes or tyre wear - as well as larger particulate matter (PM10) were estimated. Average day and night-time levels were also estimated.

Using statistical models to analyse the data, the researchers found that increases in traffic related air pollutants - especially PM2.5 - were associated with 2% to 6% increased odds of low birth weight and 1% to 3% increased odds of being small for gestational age, even after taking account of road traffic noise.

There was no evidence that increasing road traffic noise exposure was independently associated with birth weight but the authors say they "cannot rule out that an association might be observed in a study area with a wider range of noise exposures."

They also point to some study limitations, such as the potential for exposure misclassification. However, the findings held true after other potentially influential factors were taken into account, such as mother's age, ethnicity and deprivation.

"Our findings suggest that air pollution from road traffic in London is adversely affecting fetal growth," say the authors. The annual mean concentration of PM2.5 in London in 2013 was 15.3 μg m3, and the authors estimate that reducing London's annual average PM2.5 concentration by 10% would prevent approximately 90 babies (3%) being born at term with each year in London.

"With the annual number of births projected to continue increasing in London, the absolute health burden will increase at the population level, unless air quality in London improves," they conclude.

Only policy makers have the power to protect women and unborn babies, argue researchers at the University of Edinburgh in a linked editorial. And they warn that, though these results from the UK are concerning, "a global perspective reveals something approaching a public health catastrophe."

They point to Beijing, where air quality levels were improved during the 2008 Olympics, as an example of what can be achieved with coordinated action - and say 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."

Today's study "should increase awareness that prenatal exposure to small particle air pollution is detrimental to the unborn child," they write. However, they stress that increasing awareness without solutions for risk reduction "may serve only to increase maternal anxiety and guilt."

Broad, multi-sector action is urgently required to tackle the problem of related , and minimise risks to health of the next generation, they conclude.

Explore further: Noise from busy roads might increase heart disease risk, finds new study

More information: Impact of London's road traffic air and noise pollution on birth weight: retrospective population based cohort study, www.bmj.com/content/359/bmj.j5299

Traffic pollution is linked to poor pregnancy outcomes, www.bmj.com/content/359/bmj.j5511

Related Stories

Noise from busy roads might increase heart disease risk, finds new study

June 1, 2017
Traffic noise, as well as air pollution, could affect heart health, according to new research.

Air pollution exposure during pregnancy linked with asthma risk

February 9, 2016
Babies born to mothers exposed to air pollution from traffic sources during pregnancy have an increased risk of developing asthma before the age of 5 years, according to new findings.

Traffic noise increases the risk of heart attack

July 8, 2016
Your risk of heart attack increases with the amount of traffic noise to which you are exposed. The increase in risk - though slight - is greatest with road and rail traffic noise, less with aircraft noise. Such are the conclusions ...

Road traffic noise linked to deaths and increased strokes

June 23, 2015
Living in an area with noisy road traffic may reduce life expectancy, according to new research published in the European Heart Journal.

Long-term exposure to fine particles of traffic pollution increases risk of heart disease

April 18, 2013
The association between road traffic and heart disease has been suggested in several studies. In 2012 a large prospective cohort study from Denmark showed that traffic noise was significantly associated with risk of heart ...

Recommended for you

Searching for a link between achy joints and rainy weather in a flood of data, researchers come up dry

December 13, 2017
Rainy weather has long been blamed for achy joints. Unjustly so, according to new research from Harvard Medical School. The analysis, published Dec. 13 in BMJ, found no relationship between rainfall and joint or back pain.

Mistletoe and (a large) wine: Seven-fold increase in wine glass size over 300 years

December 13, 2017
Our Georgian and Victorian ancestors probably celebrated Christmas with more modest wine consumption than we do today - if the size of their wine glasses are anything to go by. Researchers at the University of Cambridge have ...

How well can digital assistants answer questions on sex?

December 13, 2017
Google laptop searches seem to be better at finding quality online sexual health advice than digital assistants on smartphones, find experts in the Christmas issue of The BMJ.

Healthy eating linked to kids' happiness

December 13, 2017
Healthy eating is associated with better self-esteem and fewer emotional and peer problems, such as having fewer friends or being picked on or bullied, in children regardless of body weight, according to a study published ...

Owning a pet does not seem to influence signs of aging

December 13, 2017
Owning a pet does not appear to slow the rate of ageing, as measured by standard indicators, suggest the authors of a study published in the Christmas issue of The BMJ.

Increased air pollution linked to bad teenage behavior

December 13, 2017
A new study linking higher levels of air pollution to increased teenage delinquency is a reminder of the importance of clean air and the need for more foliage in urban spaces, a Keck School of Medicine of USC researcher said.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.