Which medication is a known risk factor for spina bifida when used during pregnancy?

Which medication is a known risk factor for spina bifida when used during pregnancy?

• A. Valproic acid
• B. Ibuprofen
• C. Acetaminophen
• D. Penicillin

Answer: (A)

Exposure to certain medications during the early weeks of pregnancy can disrupt neural tube formation, which normally closes by about days 28–32 of gestation. Valproic acid is a known teratogen in this critical window and is strongly associated with neural tube defects such as spina bifida. Its effect is thought to involve interference with neural tube closure and folate metabolism, increasing the risk when exposure occurs during organogenesis. Because of this, women of childbearing potential are advised to avoid valproate if possible, use the lowest effective dose if no alternatives exist, and take high-dose folic acid before conception to help mitigate risk. The other medications listed—ibuprofen, acetaminophen, and penicillin—do not have the same strong association with neural tube defects; they may carry other risks in pregnancy but are not known primary risk factors for spina bifida.