Exposure To BTEX During Pregnancy Associated With Preterm Birth In African American Women, Study Shows

African American women are more likely than white women to have adverse pregnancy outcomes. While the reasons for this are multifactorial, a recent Henry Ford Health study found that exposure to a group of volatile organic compounds called BTEX may contribute to this risk.

"BTEX (which stands for benzene, toluene, ethylbenzene and xylene) is found in petroleum and prevalent in car exhaust," says Jennifer Straughen, Ph.D., an epidemiologist at Henry Ford Health who led the study. "In previous work, we found that BTEX exposure was linked to preterm birth. And as Detroit has a large African American population, they may be exposed to higher amounts of BTEX."

To conduct the study, Dr. Straughen and her colleagues extracted DNA from maternal blood that was collected during the second trimester of pregnancy. They found that mothers with higher BTEX exposure had changes in DNA methylation.

"DNA contains genes, which tells us who you are and what you look like - even things like whether cilantro tastes good to you or tastes like soap," says Dr. Straughen. "DNA methylation helps control whether genes are turned on or off, kind of like a lightbulb. We think BTEX is linked to preterm birth because it may create changes in DNA methylation."

How Much BTEX Exposure Is Too Much?

But how much BTEX exposure should you worry about? After all, living in the United States - or anywhere on the globe with cars - means it is virtually impossible to avoid BTEX exposure.

"It's currently unknown how much BTEX exposure can affect pregnancy outcomes," says Dr. Straughen. "And I don't think we have described all of the health effects of BTEX. But we're conducting a large study funded by the National Institute of Environmental Health Sciences where we're recruiting pregnant moms from Detroit. We're hoping to measure their exposure to not only BTEX but to other volatile organic compounds as well. We want to determine whether they're associated with an increased risk of preterm birth and we want to see how BTEX exposure could lead to preterm labor."

Reviewed by Jennifer Straughen, Ph.D., an epidemiologist at Henry Ford Health.