Prenatal obesity linked to congenital heart defects

A new study suggests that women being obese, but not overweight during pregnancy may have to face a higher risk of giving birth to children with congenital heart defects.

The study led by James L Mills and colleagues from the National Institutes of health and other organizations showed that women with obesity during pregnancy were 15 percent more likely than those with a normal body mass index to have children with a congenital heart defect.

In the study, obesity was defined as having a body mass index of greater than 30.  Morbid obesity was defined as having BMI of equal to or greater than 40.

For the study, Mills and colleagues compared 7392 infants born with congenital heart defects with 56,304 controls without the conditions for their mothers' weight statuses. The cases and controls were born between 1993 and 2003 in New York State, but excluding New York City.

The researchers found the severity of obesity was linked to the risk of congenital heart defects.  Morbidly obese women were 33 percent more likely than those with a BMI of 30 to 39.9.

Children born to obese women had a significantly higher risk for atrial septal defects, hypoplastic left heart syndrome, aortic stenosis, pulmonic stenosis and tetralogy of fallout, according to the study report.

However, the researchers did not find any association between being overweight during pregnancy and risk of congenital heart defects.

The findings were reported in the current issue of the American Journal of Clinical Nutrition.

Congenital heart defects are found in about 35,000 infants or one in every 125 infants each year in the United States.

David Liu