It should come as no surprise that if an expecting mother breathes air of poor quality, her child might suffer for it. Lung development trouble, premature births, and other complications have all been associated with severe air pollution. However, a new study has now linked air pollution with autism as well.

This is not the first time risk of autism development has been tied to maternal air pollution exposure. However, according to researcher Marc Weisskopf, the senior author of the new study, the specificity of these latest findings make the study of particular importance, as it "rules out many other possible explanation" for the results.

The study was published yesterday in the journal Environmental Health Perspectives, and details how Weisskopf and his colleagues asessed a cohort of more than 116,000 US mothers whose pregnancies began as early as 1989. The researchers collected data on where participants lived during their pregnancies, as well as data from the US Environmental Protection Agency (EPA) and other sources on localized levels of fine particulate matter air pollution.

Among the children born to these women, 245 were diagnosed with autism spectrum disorder (ASD) and compared to a selected control group of 1,522 children born without ASD during the same window of time.

After calculating fine air pollution (PM 2.5) each child was exposed to during each trimester, the researchers found that unborn children are more vulnerable to air pollution during the third trimester. During this time, if a mother is exposed to high concentrations of air pollution, the chances of their child developing ASD spikes well beyond the norm.

"The evidence base for a role for maternal exposure to air pollution increasing the risk of autism spectrum disorders is becoming quite strong," Weisskopf said in a statement. "This not only gives us important insight as we continue to pursue the origins of autism spectrum disorders, but as a modifiable exposure, opens the door to thinking about possible preventative measures."

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