Swiss to vote on total ban on smoking in enclosed public places. Reuters

Pregnant women who are both overweight and smoke are putting their babies' hearts at risk, according to a study published online in the journal Heart.

Researchers from the University Medical Center Groningen, The Netherlands, studied the impact smoking by obese pregnant mothers has on the heart of the unborn baby. They found that the risk for congenital heart defects in babies increased with around eight in every 1,000 babies affected when their obese moms smoked during pregnancy.

The authors analysed and compared 797 children and foetuses born between 1997 and 2008 with congenital heart anomalies and no other defects with 322 children and foetuses with chromosomal anomalies but without cardiac defects.

They found that obese pregnant mothers with a body mass index (BMI) of 25 or more who smoked, were more than 2.5 times likely to have a child with congenital heart anomalies than mothers who either smoked but were not overweight or mothers who were obese but did not smoke.

The authors insisted that overweight women who wished to become pregnant should be encouraged to lose weight and stop smoking to avoid endangering their babies' hearts.

Facts about congenital heart defects:

    • Congenital heart defects are present at birth and are the most common type of major birth defects. The cause of congenital heart defects is detected in very few cases.
    • Symptoms for congenital heart defects depend on the type and severity of the particular defect. Some defects may not have any symptoms, while others might cause a baby to have bluish tinted nails or lips.
    • Babies with congenital heart anomalies may have fast or troubled breathing, may tire easily when feeding, or may feel very sleepy. Due to this, they may not gain weight.
    • Congenital heart defect doesn't cause chest pain.
    • Children and adults with congenital heart defect can develop health problems such as irregular heart beat (arrhythmias), increased risk of infection in the heart muscle (infective endocarditis), or the heart might become weak.
    • In case of severe defects, congenital heart disease can lead to heart failure, a condition in which the heart can't pump blood strongly throughout the body.
    • Less severe congenital heart defects are not diagnosed until children are older. Minor defects often don't have symptoms.
    • People with congenital heart defect need to do routine checkups by a cardiologist to stay healthy throughout their lives.