In the United States, the Food and Drug Administration (FDA) assigns each medication to a Pregnancy Category according to whether it has been proven to be harmful in pregnancy. Carbamazepine (the medicine in Carbatrol) is listed in Pregnancy Category D. This means that there is a risk to the baby, but the benefits may outweigh the risk for some women. A warning appears in the package insert.

This warning sounds grim but in fact a large majority of women who use Carbatrol during pregnancy have normal, healthy babies. Certain types of defects, including minor defects of the face or fingernails and developmental delay, are increased but they are still relatively uncommon. The risk of defects is higher for women who take more than one seizure medicine. Women with a family history of birth defects also have a higher risk.

All women who are capable of becoming pregnant should take 0.4 mg (400 mcg) of the vitamin called folic acid every day because it helps to prevent birth defects called neural tube defects, malformations of the brain or spinal cord. The most common of these is spina bifida, which affects about 1 in 200 babies of women who take carbamazepine during the first 4 to 6 weeks of pregnancy. Women at high risk of having a baby with one of these defects (such as those who have had a previous baby with spina bifida) should take a much larger dose—4 mg (4000 mcg) per day—if they are considering pregnancy.

Women with epilepsy who are pregnant or thinking about becoming pregnant should talk to their doctor about the medications they are taking. Because taking more than one seizure medicine may increase the risk of birth defects, doctors sometimes gradually reduce the number or amount of seizure medicines taken by women planning for pregnancy. This is not done routinely, however. The risk of seizures increases when medications are withdrawn, and seizures—particularly complex partial seizures and tonic-clonic seizures—can injure the baby. Because having these types of seizures may harm the baby, it’s important not to stop taking seizure medicines or reduce the amount without the doctor’s OK.

If the mother is taking Carbatrol, a breast-fed baby will get a tiny amount of it in the breast milk. It should not be harmful for a healthy, full-term baby.