Congenital heart defects are the most common birth defect found at birth, and they affect 8 out of every 1,000 newborns in the United States. Genetics can play a role, as well as lifestyle factors. Sadly, a cause is only found in 15 percent of cases of this common birth defect.

According to a new study, published in the medical journal Heart, being both overweight and continuing to smoke in pregnancy can increase the risk that your baby will have a congenital heart defect.

Researchers from the University of Groningen in the Netherlands looked at data from nearly 800 babies – born alive and stillborns – as well as aborted fetuses with congenital heart defects. They compared these babies with 322 healthy babies and aborted fetuses that had no heart defects.

After taking into account the pregnant women’s alcohol consumption, education level, and other factors, the scientists concluded that maternal smoking and being overweight during pregnancy put the baby at 2.5 percent higher risk for congenital heart abnormalities.

In this study, women who were classified as “overweight” had a body mass index (BMI) of over 25. “Obese” women had a BMI of 30 and above.

Overweight moms who smoked in pregnancy tripled their baby’s risk of having outflow tract obstructive heart abnormalities – which means the baby’s blood flow from the heart’s ventricles to the pulmonary artery or aorta was reduced.

This research study only adds to the growing body of research, which links maternal smoking and being overweight to causing pregnancy complications – including miscarriage and stillborn, stunted growth in the womb, and premature birth.

The bottom line – try to lose weight before pregnancy, and avoid smoking when you’re expecting. Both of these risk factors together can contribute to increasing congenital heart defects.

Overview of Congenital Heart Defects

In the United States, more than 35,000 babies are born with congenital heart defects. Sometimes, the heart defect is so slight that the child is healthy for many years before anything is detected. Other times, the heart defect can be severe that it becomes life threatening and requires immediate surgical treatment.

Heart defects can affect the interior wall of the baby’s heart; the valves inside the baby’s heart; or the arteries and veins that carry blood to the heart, or the body.

Many congenital heart defects can cause no symptoms, and a doctor may not even pick up any signs of a heart problem during a regular physical exam. When symptoms do occur, they can include fatigue, rapid breathing, poor blood circulation, and a blue-ish tint to the lips, fingernails, and skin. Heart murmurs can also be a sign of a birth defect.

Congenital heart defects are the leading cause of birth-defects-related deaths. Fortunately, advances in medical diagnosis and heart surgeries have dramatically increased the survival rate for children with serious heart problems. In the United States, an estimated 1.4 million people live with congenital heart defects, and most of these live normal lives. The outlook for children with congenital heart defects is much better today. Many children will simply need regular checkups with a cardiologist. Many do live active and productive lives.

To learn more about Congenital Heart Defects (CHD), check out the National Heart, Lung, and Blood Institute’s page on CHD.

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This news article was last updated  on January 30, 2012.