cigaretteAccording to a new study that will be highlighted this weekend at the Pediatric Academic Societies (PAS) annual meeting, women, particularly younger women, are still smoking while pregnant, putting their newborns at risk for congenital heart defects.

Patrick Sullivan, MD, lead author of the study and clinical fellow in pediatric cardiology at Seattle Children’s Hospital, said maternal smoking seemed to place newborns at a 50-70 percent greater risk for specific heart anomalies. The risk was highest in the heaviest smokers.

 “Ongoing cigarette use during pregnancy is a serious problem that increases the risk of many adverse outcomes in newborns,” said Sullivan. “Our research provides strong support that smoking while pregnant increases the risk of specific heart defects.”

Sullivan and his research team used birth certificate data and hospital discharge records from Washington State to determine if maternal smoking during the first trimester of pregnancy is linked to heart defects and if so, what types of defects. They identified 14,128 children born with a variety of heart defects from 1989-2011. They matched these cases on birth year to 60,938 children without heart defects in the same birth certificate database. Then, they compared the proportion of children with heart defects whose mothers reported smoking during pregnancy to the proportion of children without heart defects whose mothers smoked, controlling for other potentially confounding risk factors for heart defects.

Results showed that children with heart defects, particularly anomalies of the right side of the heart and defects in the atrial septum, or the wall separating the two top chambers of the heart, were more likely than those without heart defects to have been born to mothers who smoked, and the risk was highest in the heaviest smokers. In addition, although women 35 years of age and older were less likely to smoke during pregnancy than younger women, older women had a higher risk of having a child with a heart defect if they smoked.

Researchers also found that “despite largely successful public health efforts to reduce smoking in the general American public over the past few decades” about 10 percent of women giving birth in recent years reported smoking during pregnancy. They estimated that maternal smoking during the first trimester may account for 1 to 2 percent of all heart defects.

“I care for kids with complex congenital heart disease on a daily basis, and I see these kids and their families enduring long hospitalizations with multiple, highly invasive and risky procedures, often sustaining serious long-term complications as a result of their disease,” Sullivan said. “I saw this research as an opportunity to identify what might be a preventable cause of congenital heart defects, and the hardship that comes with it.”

More than 100 physicians and researchers from Seattle Children’s will be attending and presenting at the annual PAS meeting, which takes place this year May 3-6 in Vancouver, BC. If you are a member of the media and would like to speak with Sullivan or other presenters from Seattle Children’s, please email