The causes of obesity in children can be fairly easy to pinpoint: a poor diet and inactivity. But sometimes it’s more than that — the origin sometimes goes back all the way to the womb. Researchers are looking to a particular source for answers: moms. A recent study published in the journal Obesity found that mothers exposed to a chemical called perfluorooctanoic acid, or PFOA, were more likely to have obese children.

The moms in the study lived in Cincinnati, downstream from an industrial plant along the Ohio River. PFOA is used to make materials that repel oil and water, like firefighting foam and nonstick coatings. Researchers measured children’s heights, weights and the amount of fat tissue they had and found that those children had higher amounts of body fat by age 8 compared with kids whose mothers had less exposure to the chemical during pregnancy.

The researchers cautioned that the study does not prove that the chemicals caused obesity, but is merely a link between the chemical and weight. Still, the researchers say it is enough of a link to investigate further to see if the childrens’ weight is affected later in life.

Another study from the West Virginia University School of Public Health found that PFOAs are in 98 percent of the population’s bloodstream and can raise the risk of cardiovascular disease. So how do you steer clear of such toxins? Limit your contact with the chemical by avoiding the two biggest sources: nonstick cookware and plastic-packaged foods such as microwave popcorn. More research is needed, and full-on alarm is not necessary, but in the meantime it’s best to steer clear of PFOAs.

Perhaps of greater concern are phthalates, chemicals found in many cosmetics and even nonorganic crops. Moral of the story? Read your labels.