Rosh Psychiatry Board Practice Exam

Which medication has the lowest risk of causing major congenital malformations?

1. Carbamazepine

2. Lamotrigine

3. Lithium

4. Valproic acid

The correct answer is: Lamotrigine

Lamotrigine is associated with the lowest risk of causing major congenital malformations when compared to the other medications listed. Research indicates that while there is still a potential risk for congenital malformations with lamotrigine, it is significantly lower than the risks associated with carbamazepine, lithium, and especially valproic acid. Valproic acid is known to carry a high risk of teratogenic effects, particularly resulting in neural tube defects and other significant malformations. Carbamazepine also has a well-documented risk for similar issues, although not as high as that of valproic acid. Lithium, while potentially having some associated risks, has a lower incidence of major congenital malformations than the two mentioned previously, but still poses a concern. In summary, lamotrigine's profile of safety in pregnancy makes it the preferred choice for treating conditions like epilepsy or bipolar disorder in women who are or may become pregnant, as it presents the least risk for major congenital malformations among these medications.