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Traffic pollution has similar birth weight effect as smoking

http://www.sciencewa.net.au/3768-traffic-pollution-has-similar-birth-weight-effect-as-smoking.html

Dec. 1, 2011

Description: Traffic_pollution

When exposed to traffic emission levels within national air quality guidelines, healthy pregnant women, with no known recorded risk factors for low birth weight, were found to give birth to infants an average 58g lighter than expected. Flickr Matthew Klein

PERTH mothers provide the first evidence of a link between suburban traffic pollution and reduced foetal growth rate—with rate of reduction similar to half the effect of maternal smoking.

In a joint project between the University of Western Australia and the Telethon Institute for Child Health Research, researchers used traffic emission data from areas of low industrial activity to assess the exposure of 1000 women who gave birth between 2000 and 2006.

Chief Investigator Assistant Professor Gavin Pereira says, “Internationally there have been quite a few studies looking at the adverse effects of traffic emissions on a range of pregnancy outcomes”.

“This is the first time an association between maternal exposure to suburban traffic pollution and reduced foetal growth has been made.”

When exposed to traffic emission levels within national air quality guidelines, healthy pregnant women, with no known recorded risk factors for low birth weight, were found to give birth to infants an average 58g lighter than expected.

“This is about half the effect observed for maternal smoking during pregnancy,” A/Prof Pereira says.

“We expect the effect would be worse in groups of women with lower socioeconomic status, co-morbitidities and perhaps even different ethnic groups.”

The specific toxicant responsible for the reduction in foetal growth remains unknown.

“One possibility is carbon monoxide which binds to haemoglobin to from carboxy-haemoglobin; this is associated with lower oxygen intakes for the foetus and may impact foetal growth,” he says.

“Another possibility is a group of chemicals called polycyclic aromatic hydrocarbons, or particulate matter in general—the jury’s out.”

Surprisingly, there also seems to be no threshold level below which an effect is not observed, with low levels of emission still reducing growth.

“It would be nice for these types of studies to inform an acceptable level of some of the criteria of air pollutants, to be able to say that below a certain level we don’t observe effects so that this threshold could become the national standard,” says A/Prof Pereira.

“But at the moment, the results can only suggest that we should be adapting our means of environmental air monitoring”

According to A/Prof Pereira, the results not only call for a change in the way we think about monitoring pollutants, but send a message to the public about the need to reduce our reliance on motor vehicles.

“Preventing low birth weight and foetal growth restriction is important to ensure the best short-and long-term health outcomes for the child.”

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