Women who drink or smoke do have an increased risk of seeing this defect with their baby, as do women who are younger when they get pregnant, earlier studies have shown.
Each year, about 1,871 babies are born with the defect, according to the CDC.
While surgery can repair the problem in most cases, the birth defect can be life-threatening. Some children are left with a lifetime of challenges with digestion and eating. Others might have trouble absorbing nutrients.