Women who eat healthily before and during pregnancy may cut the risk of their baby developing a heart problem, researchers believe.
The link is suggested by a study of 19,000 women in the US who were asked about their diet in the year leading up to pregnancy.
A healthy diet was one with plenty of fresh fish, fruit, nuts and vegetables.
Pregnant women and women trying to conceive are already advised to take certain supplements.
Experts recommend folic acid to reduce the risk of other birth defects like spina bifida, and vitamin D for healthy bones and teeth.
In England, the government’s Healthy Start scheme provides vouchers for pregnant women that can be used to buy milk and vegetables.
In the study, published in Archives of Diseases in Childhood Fetal & Neonatal Edition, half of the women had babies with heart problems while the other half did not.
When the researchers compared the diets of these two groups they found a healthier maternal diet was associated with a lower chance of congenital heart defects.