Nov. 29, 2000 -- Chalk another one up for folic acid. Experts agree that folic acid is critical for pregnant women -- or those trying to get pregnant -- who want to prevent birth defects of the brain and spinal cord. Now researchers have shown that folic acid -- a B vitamin -- also may reduce the risk of other birth defects associated with common medications some women may have to take while pregnant.
Although doctors try to limit the amount of medications pregnant women must take, serious medical conditions like epilepsy, infections, and high blood pressure require drugs that pose a risk to a developing baby. Birth defects associated with these drugs may affect development of the heart, urinary tract, and mouth -- such as a cleft lip or palate.
One theory is that these drugs deplete the mother's level of folic acid or interfere with her absorption of folic acid. Not all women who take such drugs have babies born with defects, but those who do usually have taken the medications early in the first trimester of their pregnancy when important organ development is underway in the fetus.
In a study published in the Nov. 30, 2000 issue of The New England Journal of Medicine, researchers led by Sonia Hernandez-Diaz, MD, of Boston University, found that women who took one or more drugs that interfere with folic acid without also taking a folic acid supplement while pregnant had a much higher risk of having a baby with a birth defect. Nearly an eight times greater risk of having a baby born with a heart defect and a five times greater risk of having a baby born with a cleft lip or palate, as a matter of fact. Women who did take folic acid in a daily multivitamin in addition to the drugs had a significantly reduced risk that their babies would be born with any of these defects.
Drugs mothers took that increased the risk of birth defects in their babies included:
- Antiepilepsy drugs Dilantin, Tegretol, phenobarbital, and primidone
- Trimethoprim -- one of the drugs in the antibiotics Bactrim and Septra -- which are used to treat urinary tract infections
- Triamterene -- part of Maxzide and Dyazide -- which treats high blood pressure
- The rheumatoid arthritis drug, sulfasalazine
"[This study] is showing that folic acid can reduce the risk of those birth defects," says Lynne B. Bailey, PhD. "The advice would certainly be to stop taking these medications, but if the pregnancy is not planned ... this gives you more reason to adhere to the recommendations [to take folic acid]." Bailey is a professor of human nutrition at the University of Florida in Gainesville.
The U.S. Public Health Service recommends that women get at least 400 micrograms of folic acid, or folate, per day to prevent birth defects, but the CDC says most women only get about half that amount on a regular basis. In addition to getting folate through prenatal and multivitamins, another way to boost intake of folic acid is from the plate. Some good sources include:
- Most breakfast cereals
- Dark green leafy vegetables
- Oranges and orange juice
- Dried beans
- Chick peas
- Wheat germ
- Whole-grain breads
The best strategy is a combination of a supplement containing folic acid and varying the diet to include more folate-rich foods, says Bailey. In 1998, the FDA began requiring that certain foods such as breakfast cereals, breads, and pastas be enriched with folate after studies proved the vitamin significantly reduced the risk of birth defects. A few ready-to-eat cereals contain the entire daily requirement for folate in just one serving.
Bailey says there are reasons other than preventing birth defects to make sure you get enough folic acid. "The folate-rich food sources are also good sources of other nutrients that are considered heart-healthy," she says. "Folate is also associated with reducing a risk factor for heart disease. If you change your diet and the diet of your family to include more folate-rich food you're also potentially reducing your risk of heart disease and possibly even cancer."