According to the U.S. Public Health Service, U.S. Preventative Services Task Force, March of Dimes, the Institute of Medicine, the American College of Obstetricians and Gynecologists (ACOG), and the Centers for Disease Control and Prevention (CDC), all women of childbearing age in the United States who are capable of becoming pregnant should consume 0.4 mg (400 mcg) of Folic Acid per day for the purpose of reducing their risk of having a pregnancy affected with spina bifida or other neural tube defects (NTDs). Most prenatal supplements contain between 0.4mg and 0.8mg of Folic Acid and either is considered safe and acceptable for women planning to become pregnant or who are pregnant. In addition, women should eat a healthy diet including foods rich in Folic Acid. This is the only sure way a woman can get all the Folic Acid and other vitamins she needs. Most women get only about 200 micrograms of Folic Acid a day from their diets.

The body can absorb almost 100 percent of the synthetic form of Folic Acid. This is why it is recommended that women who could become pregnant consume 400 micrograms a day of the synthetic form.

However, women should not take more than 1,000 micrograms (mcg) (or 1 milligram (mg)) without their doctor’s advice.