Folic acid is a type of B vitamin that's a crucial for your health, especially when you're trying to get pregnant and during pregnancy. Up to 70 percent of all neural tube defects (NTDs)—birth defects of the brain and spine—could be prevented if every woman of childbearing age took folic acid daily, according to the Centers for Disease Control and Prevention (CDC). It's found in certain vegetables, nuts, and legumes but most moms-to-be don't eat enough of these foods regularly to get all the folic acid they need, which is why taking prenatal vitamins that contain it is so important.
Taking folic acid early in pregnancy is important because the neural tube closes 24 to 28 days after conception, according to James L. Mills, M.D., chief of the pediatric epidemiology section of the National Institutes of Child Health and Human Development at the National Institutes of Health, and a renowned expert in the field. "By the time most women discover they are pregnant, the neural tube is probably closed," he says.
So what can you do if you haven't taken your folic acid and are well into your pregnancy? First of all, it's never too late to start making sure to get enough of this important vitamin for you and your baby. "There may be additional benefits to taking folate through pregnancy," says Margaret Thomson, R.N., genetic disease program specialist in the Genetic Disease Branch of the California Department of Health Services. "Pregnant women who maintain high blood levels of folate were less likely to have preterm or low birth-weight babies, according to a recent study published in the American Journal of Clinical Nutrition."
Folic acid is a form of folate, which occurs naturally in foods, and is available in synthetic form in vitamin pills. Foods that contain folates include orange juice, green leafy vegetables, and beans. Fortified breakfast cereals, enriched grain products, and vitamins contain a synthetic form of folic acid. The synthetic form is more easily absorbed by your body than the natural form.
While researchers don't know why folic acid helps prevent birth defects, it has been shown to significantly prevent major birth defects, especially those that can occur very early in pregnancy, often before women even know they're expecting. These include problems with your baby's developing brain and spinal cord, called neural-tube defects (NTDs), like spina bifida (the leading cause of childhood paralysis) and anencephaly (a fatal condition in which a baby is born with a severely underdeveloped brain and skull).
The vitamin may also help keep your baby from developing a heart defect, cleft lip, or cleft palate, and has been linked to the prevention of autism. A recent UC Davis study found that mothers who took the amount of folic acid found in most prenatal vitamins were less likely to have children with autism spectrum disorders (ASD), even if they'd been exposed to household pesticides, a known risk factor linked to autism.
"Half of all pregnancies in the U.S. are unplanned," says Diane Ashton, MD, deputy medical director for the March of Dimes. "So it's important that all women of child-bearing age take folic acid supplements every day, just to be safe, even if they're not trying to get pregnant just yet."
In fact, research from the University of Texas Medical Branch at Galveston revealed that taking folic acid for at least a year before conceiving may reduce the risk of preterm birth by 50 to 70 percent. About 13 percent of babies are born prematurely every year. Another study found that women with folic acid deficiencies were two to three times more likely to have a premature baby or a baby of low birth weight than those who got enough of the vitamin. Luckily, prenatal vitamins are packed with folic acid, and taking one every day before you get pregnant and during pregnancy can make a huge impact on keeping you and your baby healthy.
The March of Dimes, the CDC, and the Institute of Medicine recommend that all women consume at least 400 micrograms of the synthetic form a day, and that pregnant women consume 600 micrograms, either from a prenatal vitamin or multivitamin, or by consuming a fortified breakfast cereal that contains 400 micrograms of folic acid in one bowl. Because the body absorbs folic acid better from vitamins than from food, you're better off taking a prenatal vitamin that contains folic acid every day while you're trying to get pregnant and during pregnancy. (Most prenatal vitamins contain 800 to 1,000 micrograms per tablet, so you'll definitely get enough in pill form.)
It's possible to take too much folic acid. A 2014 study published in the Journal of Epidemiology & Community Health found that women who took folic acid supplements were twice as likely to die of breast cancer. Other research has found a correlation between supplemental folate and asthma, heart problems, leukemia, and ectopic pregnancy. For women who are unable to absorb synthetic folate, it may increase their risk of miscarriage.
The bottom line? While folate is critical before and during early pregnancy, it may be smart to taper off the vitamin after the first trimester. After that, it's best to get folate through food sources; keep in mind that fortified foods like breakfast cereals don't pose the same risk as vitamin pills because the body metabolizes them differently.
It's always a good idea to eat plenty of folate-rich foods, which also contain many other important vitamins, minerals, and nutrients. Foods that are rich in folates include:
Since 1998, the U.S. Food and Drug Administration has required that bread, cereal, rice, and pasta be fortified with folic acid, which your body can absorb more easily than natural folates. Foods that may be labeled "enriched" (required to have 140 micrograms of folic acid per 100 grams of grain) include:
If you've already had a baby with an NTD, consult your doctor about how much folic acid you should take before your next pregnancy. Studies have shown that taking a larger dose (4 milligrams) beginning at least one month before pregnancy and during the first trimester reduces the risk of having another affected pregnancy by about 70 percent.