The US Food and Drug Administration (FDA) has approved folic acid to be added to corn masa flour.
This allows producers to add up to 0.7mg of folic acid with every pound of corn masa flour.
This requires being consistent with the levels of other enriched cereal grains.
A synthetic form of folate, folic acid contains vitamin B, which helps pregnant women prevent neural tube defects affecting the brain, spinal cord and the spine of a newborn.
FDA Centre for Food Safety and Applied Nutrition director Susan Mayne said: "Increased consumption of folic acid in enriched flour has been helpful in reducing the incidence of neural tube defects in the general population.
"Our analysis shows that adding folic acid to corn masa flour will help increase the consumption of folic acid by women who consume this flour as a staple in their diet."
Corn masa flour is produced when corn is grinded after being cooked in alkali.
Manufacturers are currently allowed to add folic acid in breakfast cereals and other foods at specified levels as an optional ingredient.
It should also be added to some enriched grains and related products such as rolls, noodles, breads and pasta.
This will help consumers receive enough folic acid in their diets.
In order to determine if adding folic acid to corn masa flour is safe for human consumption, the FDA has examined the toxicological data, projected human dietary exposure, as well as other associated information.
It has also evaluated whether folic acid maintains stability in the flour.
