Folic acid, also called folate, is a B vitamin, essential for the division of all body cells and the production of DNA and RNA, the genetic material of life. Without it, nothing can grow—not even a single hair or fingernail—and healing cannot take place. Folic acid is found in orange juice, leafy green vegetables, and beans. And, the Food and Drug Administration (FDA) requires folic acid to be added to enriched grains (eg, breads, cereals, and pasta).

Through its role in the cellular processes required for normal fetal development, folic acid helps prevent neural tube defects (NTDs). Occurring in about one in 1,000 births, NTDs are among the most serious birth defects in the US. NTDs occur when the neural tube, which forms the brain and spinal cord, fails to close. Folic acid supports the normal fusion of the neural tube. "If we give folic acid, the normal (spinal closure) process goes to completion," says Dr. Donald R. Mattison, former medical director for the March of Dimes Birth Defects Foundation.

NTDs include anencephaly and spina bifida. Anencephaly occurs when a large portion of a baby's brain is not fully formed. This condition is incompatible with life. Spina bifida, which occurs when a fetus' spine does not close completely, is the most common NTD. According to the March of Dimes, the risk of NTDs could be reduced by 70% if women consumed an adequate amount of folic acid. Another study suggests that folic acid may prevent 50% of birth defects across the board, including cleft lip and cleft palate.

These statistics are impressive, but there is a catch: Women must consume sufficient levels of folic acid prior to conception since the neural tube is formed very early in pregnancy. Bolstering folic acid status early—about a month prior to starting to try to conceive—ensures that a woman has an adequate amount in her body at conception, explains Dr. Mattison.

The problem, however, is that nearly half of all pregnancies in the US are unplanned. Because of this, the March of Dimes and US Public Health Service have recommended that all women of childbearing age, including all teenage girls, consume 400 micrograms (mcg) of folic acid each day. Most multivitamins contain this amount, as do some fortified breakfast cereals. Other good food sources include beef liver, black eyed peas, spinach, asparagus, and baked beans.

Other countries also fortify their food with folic acid. Canada, for example, has seen signs of benefit with its fortification program—a decrease in the number of babies born with heart defects, suggesting that folic acid can offer protection beyond neural tube defects. Taking folate and iron may offer additional benefits, like reducing the number of infants born with low birth weight and reducing infant mortality .