Pollution exposure during pregnancy linked to lower IQs

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A study of 249 pregnant mothers was performed in New York City. Air monitors were worn on backpacks during the last few months of their pregnancy. Most of the pollution they were exposed to was mostly from cars, buses and truck exhaust.

At age 5, before starting school, the children were given IQ tests. Those exposed to the most pollution before birth scored on average four to five points lower than children with less exposure.

That's a big enough difference that it could affect children's performance in school, said Frederica Perera, the study's lead author and director of the Columbia Center for Children's Environmental Health.

Dr. Michael Msall, a University of Chicago pediatrician not involved in the research, said the study doesn't mean that children living in congested cities "aren't going to learn to read and write and spell."

But it does suggest that you don't have to live right next door to a belching factory to face pollution health risks, and that there may be more dangers from typical urban air pollution than previously thought, he said.

"We are learning more and more about low-dose exposure and how things we take for granted may not be a free ride," he said.

While future research is needed to confirm the new results, the findings suggest exposure to air pollution before birth could have the same harmful effects on the developing brain as exposure to lead, said Patrick Breysse, an environmental health specialist at Johns Hopkins' school of public health.

"It's a profound observation," he said. "This paper is going to open a lot of eyes."

The study in the August edition of Pediatrics was released Monday.

In earlier research, involving some of the same children and others, Perera linked prenatal exposure to air pollution with genetic abnormalities at birth that could increase risks for cancer; smaller newborn head size and reduced birth weight. Her research team also has linked it with developmental delays at age 3 and with children's asthma.

The researchers studied pollutants that can cross the placenta and are known scientifically as polycyclic aromatic hydrocarbons. Main sources include vehicle exhaust and factory emissions. Tobacco smoke is another source, but mothers in the study were nonsmokers.

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