Perspective:

Maternal obesity is recognized as a risk factor for congenital heart defects among offspring. This study shows that certain defects (aortic arch defects, atrial septal defects, and persistent ductus arteriosus) were associated with increasing BMI, but others were not. The mechanism by which obesity increases the risk of fetal malformations may be related to diabetes, insulin resistance, inflammation, endothelial dysfunction, and oxidative stress causing adverse gene expression and organ development. Prior animal studies have shown that hyperglycemia is associated with increased risks of congenital malformations, and that supplementation with antioxidants (vitamins C and E) could potentially inhibit damage by free oxygen radicals. Maternal malnutrition may also contribute to congenital defects, as obese women have been observed to have lower levels of folic acid and are less responsive to supplementation in standard doses. Further studies could examine specific associations between fat distribution such as visceral fat. Given the high rates of obesity in the United States, primary prevention efforts aimed at reducing obesity among women of childbearing age should be a priority.