Late Term Pregnancy Exposure to Pollution Doubles Autism Risk for Children, Harvard Study Finds


Pregnant women may want to consider spending the last few months of their pregnancies deep in a forest or on a deserted island breathing in fresh, clean air, as startling new research finds that late-term (third trimester) exposure to common particulate pollution can double the autism risk for the unborn child compared with pregnant women who are exposed to unpolluted air during the final months of pregnancy.

What’s perhaps most startling about the autism risk from polluted air is that it’s not just industrial pollution (although the research found that plays a part in the increased risk as well), but the research noted that both fire pollution and exhaust from vehicles were also significant factors in increasing the fetus’s risks. And the greater the exposure, the more significant the autism risk for the child, the researchers found.

The study, conducted by the Harvard School of Public Health, was published online in the journal Environmental Health Perspectives. The researchers looked at the children of more than 116,000 women who participated in the Nurses’ Health Study II, which began in 1989. “The researchers collected data on where the women lived while pregnant and levels of particulate pollution,” explains the Huffington Post. “They then compared the prenatal histories of 245 children with autism spectrum disorder to 1,522 normally-developing children, all born from 1990 to 2002.”

What the researchers found was that while there was no association between particulate pollution exposure before, or in the early stages of pregnancy, or even once the child was born, the autism risk doubled if there was high level exposure to particulate pollution in the third trimester.

According to Harvard epidemiologist Marc Weisskopf, who led the study, the link between a pregnant woman’s exposure to air pollution and the increased autism risk is “becoming quite strong,” he said in the Post.

And according to the Post, earlier research studies also found “an autism-pollution connection, including a 2010 study that found the risk of autism doubled if a mother, during her third trimester, lived near a freeway, a proxy for exposure to particulates.” But, reports the Post, “this is the first to examine the link across the United States,” and it bolsters the findings of the previous studies.

Fortunately, the EPA recently tightened air quality standards for fine particulate pollution. The new regulations must be implemented by 2020 to help reduce the risks of asthma, lung cancer and cardiovascular disease, all of which have already been connected to pollution exposure. But it’s not clear if those restrictions will be strong enough to decrease the autism risk.

Autism diagnoses have skyrocketed to one in 68 children, according to the most recent data in 2010. That number is up significantly from one child in 150 in 2000. Multiple risk factors have been identified as possible causes for autism including common chemicals and pesticides, but a single cause of the condition has yet to be identified and there is no cure.

Find Jill on Twitter @jillettinger

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Image: Menno Van Der Horst