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Smoking during pregnancy may raise risk of heart defects in newborns

Women who smoke during pregnancy may up the risk of their babies having heart defects.
Women who smoke during pregnancy may up the risk of their babies having heart defects.
Daniel Berehulak/Getty Images

Women who smoke during pregnancy may increase the risk of congenital heart defects in their babies, according to a new study presented at the May 3 Pediatric Academic Societies annual meeting in Vancouver, British Columbia, Canada. Study findings also showed that the more cigarettes a mother smoked while pregnant, the greater the risk her child would be born 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," lead author Patrick M. Sullivan, MD, FAAP, a clinical fellow in pediatric cardiology at Seattle Children's Hospital, said in a news release.

“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," added Sullivan.

Sullivan and his team used hospital discharge records to identify 14,218 children born with a variety of heart defects in the years 1989 to 2011. They matched these cases with 62,274 children born in the same years without heart defects. The researchers then analyzed the mother’s smoking habits based on data available on the babies’ birth certificates.

Overall, findings showed that mothers who smoked had a 20 percent greater chance of having a child with a heart defect than mothers who did not smoke. The more the mother smoked, the greater the odds were the child would have a heart defect. In addition, the study found that although women 35 and older were less likely to smoke during their pregnancy, those that did had a higher risk of having a child with a heart defect than those who did not.

Specific findings revealed that women who smoked were at a 50 percent to 70 percent risk of having a baby with anomalies of the pulmonary valve and vessels that carry blood to the lungs. There was also about a 20 percent increased risk of having a child with an atrial septal defect -- hole in the wall that separates the two chambers of the heart. These defects require surgical procedures to correct.

Despite a largely successful public health effort to reduce smoking in the general public over the past few decades, the research team found that 10 percent of women giving birth reported smoking during their pregnancies.

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