Mothers who live near heavy oil and gas development have between 40 percent and 70 percent greater chance of giving birth to babies with congenital heart defects. File Photo by Lilac Mountain/Shutterstock

July 18 (UPI) -- Pregnant women who live in close proximity to gas wells and oil refineries put their unborn infants at risk for developing pulmonary artery, aortic artery and valve defects, new research shows.

Mothers who live in areas with heavy oil and gas developments have between a 40 percent and 70 percent greater chance of giving birth to babies with congenital heart defects, according to a study published Thursday in Environment International.


"We observed more children were being born with a congenital heart defect in areas with the highest intensity of oil and gas well activity," Lisa McKenzie, a researcher at the University of Colorado and study seniors author, said in a news release.

The study included more than 3,300 infants born in Colorado between 2005 and 2011. It found those children had a higher risk of aortic artery, conotruncal, tricuspid valve and other heart defects if they were born near areas with concentrated oil and gas activity.

This research follows up on a 2014 study that showed a link between the increase in congenital heart defects cases and gas well density within 10 miles of the homes of mothers with newborns.

Each year, about 40,000 babies are born with congenital heart defects, according to the Centers for Disease Control and Prevention.

"This study provides further evidence of a positive association between maternal proximity to oil and gas well site activities and several types of congenital heart defects," she said. "Taken together, our results and expanding development of oil and gas well sites underscore the importance of continuing to conduct comprehensive and rigorous research on health consequences of early life exposure to oil and gas activities."