What is the purpose of folic acid supplementation in women of childbearing potential on antiseizure medications, particularly valproate?

• A. Reduces risk of neural tube defects; ensure appropriate daily folic acid intake (commonly 400–800 mcg, higher with high-risk regimens).
• B. Prevents weight gain
• C. Causes seizures
• D. Increases risk of neural tube defects

Answer: (A)

Folic acid helps neural tube development in the embryo. The neural tube forms very early in pregnancy, often before a woman realizes she’s pregnant, so taking folic acid beforehand is crucial. Antiseizure medications, especially valproate, raise the risk of neural tube defects by affecting folate metabolism and increasing folate needs. Taking folic acid reduces that risk, though it doesn’t guarantee prevention. The usual recommendation is a daily intake of 400–800 micrograms, with higher doses used for those at higher risk (such as on valproate or with a prior neural tube defect). Start before conception and continue through the early weeks of pregnancy. The other options don’t fit because folic acid doesn’t prevent weight gain, doesn’t cause seizures, and doesn’t increase the risk of neural tube defects.