Step 1: Understanding the Concept:
Many antiepileptic drugs (AEDs) are teratogenic. Neural tube defects (like spina bifida) occur when the brain/spinal cord fails to close properly in early pregnancy.
Step 2: Detailed Explanation:
1. Valproic Acid: It is a broad-spectrum AED but is associated with the highest risk of major malformations (about 10% risk), specifically neural tube defects. It interferes with folate metabolism and other developmental pathways.
2. Safer Options: Lamotrigine and Levetiracetam are generally considered the safest options for women of childbearing age.
Step 3: Final Answer:
Valproic acid has a well-documented and strong association with neural tube defects compared to other anticonvulsants.