Smoking and Heart Birth Defects
Maternal Smoking Linked to Congenital Cardiac Defects
Mothers who smoke any time during the month before conception through the first trimester are at higher risk for having babies with serious cardiac birth defects.
Women who smoke while pregnant expose their unborn children to toxins, placing them at risk for developing congenital heart defects, according to several studies. The damage can be done before a woman even knows she is pregnant.
“The heart’s basic structures develop very early in pregnancy, before many women realize they are pregnant,” said Sadia Malik, M.B.B.S, M.P.H. “Thus, even if a woman quits smoking at six weeks or later, her fetus will still have been exposed to the harmful effects of cigarette smoking during cardiac development.”
Malik is an assistant professor of pediatrics at the University of Arkansas for Medical Sciences (UAMS) in Little Rock, Ark. She was the lead author of a study that investigated associations between maternal smoking and congenital heart defects in babies. The study was done in collaboration with the National Birth Defects Prevention Study, a multi-state study on the causes of birth defects. Malik presented study findings at the American Heart Association’s Scientific Sessions 2006.
“From animal studies, we know that multiple components within cigarettes are harmful to the developing fetus and can cause mutations that might lead to birth defects,” Malik said.
Congenital heart defects are the most common kind of birth defect, according to the Centers for Disease Control and Prevention. These defects occur in eight to 10 of every 1,000 live births in the United States. Many infants with these defects die in the first year of life; those that do not die often need multiple surgeries, lengthy hospitalizations and life-long treatment of related disabilities.
A CDC-funded study found that the most common of these congenital heart defects were septal heart defects. A septal heart defect is when there is a hole in the heart between the right and left chambers; this disrupts the blood and oxygen flow to the body. Other defects found were conotruncal, right-side obstructive and left-side obstructive defects. A conotruncal defect is where the blood does not circulate well from the lower heart chamber; right- and left-side obstructive defects are where the blood is blocked from flowing freely from the respective side of the heart.
This study, which was published in the April issue of Pediatrics, showed that women who smoked any time during the month before conception through the end of the first trimester were more likely to give birth to babies with these heart defects than women who did not smoke. Mothers who were heavier smokers had a higher link to the defects.
“Most people know that smoking causes cancer, heart disease and other major health problems,” said Margaret Honein, Ph.D., M.P.H., one of the researchers at the CDC’s National Center for Birth Defects and Developmental Disabilities. “The indisputable fact is that women who smoke during pregnancy put themselves and their unborn babies at risk for other health problems.”
Other pregnancy and newborn health issues related to smoking include the following, according to the CDC:
- Smoking makes conception harder
- Women who smoke during pregnancy are more likely to miscarry than women who do not smoke
- Smoking can cause problems with the placenta, which is the baby’s oxygen and nutrient source
- Smoking during pregnancy can cause premature birth and low birth weight, which can increase the baby’s chance of getting sick or dying
- Babies born to women who smoke are more likely to have a cleft lip or cleft palate, both of which are birth defects
- Smoking during and after pregnancy is one of the causes of Sudden Infant Death Syndrome, also known as SIDS
