The U.S. Food and Drug Administration (FDA) lists Trileptal in Pregnancy Category C. This indicates that caution is advised, but the benefits of the medication may outweigh the potential risks. Studies in animals have shown some harm to the fetus.

Information about the safety of Trileptal in pregnancy is limited. In one retrospective study, 3 of 12 women treated with Trileptal as monotherapy or polytherapy during the first trimester had spontaneous abortions; the other 9 delivered normal babies.

Advise women who are capable of becoming pregnant to take at least 400 mcg (0.4 mg) of folic acid (folate) daily to help prevent neural tube defects. Women at high risk, such as those with a history of a neural tube defect in a previous pregnancy, should take 4000 mcg (4 mg) daily, beginning before they become pregnant.

The risk of defects is generally higher for women who take more than one AED and for women with a family history of birth defects.

About 20% to 35% of women have seizures more often during pregnancy because of changes in hormones or changes in how their AED is metabolized. It is not known if this is true for Trileptal.

Trileptal and MHD cross the placenta and are excreted in breast milk, with a milk-to-plasma concentration ratio of 0.5.