Exposure to valproic acid during pregnancy increases the risk of which CNS abnormalities?

Exposure to valproic acid during pregnancy increases the risk of which CNS abnormalities?

• A. Neural tube defects and other CNS malformations
• B. Increased brain size
• C. Enhanced neuronal migration
• D. Decreased CSF production

Answer: (A)

Valproic acid is a teratogen that disrupts early CNS development, especially during the first month when the neural tube is forming and closing. Exposure at this critical time raises the risk of neural tube defects, such as spina bifida, along with other CNS malformations. The mechanism involves interference with folate metabolism and inhibition of histone deacetylases, which alters gene expression needed for normal neurulation. The other described effects—increased brain size, enhanced neuronal migration, or decreased CSF production—aren’t typical outcomes of valproate exposure, making neural tube defects the best answer.

Valproic acid is a teratogen that disrupts early CNS development, especially during the first month when the neural tube is forming and closing. Exposure at this critical time raises the risk of neural tube defects, such as spina bifida, along with other CNS malformations. The mechanism involves interference with folate metabolism and inhibition of histone deacetylases, which alters gene expression needed for normal neurulation. The other described effects—increased brain size, enhanced neuronal migration, or decreased CSF production—aren’t typical outcomes of valproate exposure, making neural tube defects the best answer.