Women who smoke during pregnancy have a higher risk of having a child with a heart defect.

"I care for kids with complex congenital heart disease on a daily basis, and I see these kids and their families enduring long hospitalizations and often sustaining serious long-term complications as a result of their disease. Usually, the cause of a heart defect is unknown. I saw this research as an opportunity to study what might be a preventable cause of congenital heart defects," lead author Patrick M. Sullivan, MD, FAAP, clinical fellow in pediatric cardiology at Seattle Children's Hospital and a master's student in epidemiology at the University of Washington School of Public Health said in an American Academy of Pediatrics.

The team looked at hospital discharge records of 14,128 children born with heart defects between the years of 1989 and 2011. The researchers compared thee records to those of 62,274 children who were born without heart defects during the same time period.

The researchers looked at the proportion of heart defects in the offspring of mothers who smoked and compared it with how heavily they did so.

The team found mothers who smoked while pregnant were more likely to have children with heart defects than those who did not, and the risk rose in heavy drinkers.

Newborns whose mothers smoked during their pregnancy were 50 to 70 percent more likely to have anomalies of the heart valve. About 10 percent of women smoked during pregnancy.

"Women, particularly younger women, are still smoking while pregnant, despite largely successful public health efforts to reduce smoking in the general public over the past few decades," Dotor Sullivan said. "Ongoing cigarette use during pregnancy is a serious problem that increases the risk of many adverse outcomes in newborns. Our research provides strong support for the hypothesis that smoking while pregnant increases the risk of specific heart defects."