Epilepsy medication before trying to conceive

What does the evidence say about epilepsy medication before trying to conceive while trying to conceive?

1. All women with epilepsy of childbearing age are encouraged to get preconception counseling, ideally starting 1 to 2 years before trying to conceive, with folic acid guidance generally starting at 0.4 mg daily and rising to as much as 5 mg daily for those at higher risk; once pregnancy begins, antiseizure medication is generally not stopped or switched, so any change is better made beforehand. 1
2. Valproate carries roughly a 7 percent risk of a major malformation as monotherapy, compared with about 3 percent for carbamazepine or lamotrigine alone, and combining two or more antiseizure drugs raises the risk further, to around 15 percent, with risk climbing at higher doses of any single drug. 2
3. Women who are seizure-free for 9 months to a year before conception have about a 74 to 92 percent chance of staying seizure-free throughout pregnancy, and beyond physical birth defects, children exposed to valproate before birth have shown lower IQ scores and higher rates of autism spectrum disorder and ADHD compared with children exposed to other antiseizure drugs. 2
4. Several commonly used antiseizure medications interact with folate metabolism in ways that lower folate levels, and while periconceptional folic acid has shown a protective effect on some antiseizure-medication-associated neurodevelopmental outcomes in children, researchers say general agreement on the single best folic acid dose is still lacking. 3
5. As one example of how risk varies by drug, several studies covering several thousand pregnancies have not found an increased chance of birth defects with lamotrigine specifically, which is part of why a blanket switch away from all antiseizure medication isn't the goal: matching the right drug to the person is. 4

What to know about epilepsy medication before trying to conceive while trying to conceive

• Preconception counseling is recommended for anyone with epilepsy who could become pregnant, ideally starting 1 to 2 years before you plan to conceive, since that gives enough time to review your specific medication, adjust the dose, or switch to a different option if needed, all before pregnancy rather than during it.
• Most guidance points to a folic acid dose of around 5 mg a day starting before conception, higher than the standard 0.4 mg, since several seizure medications interact with folate metabolism. Valproate carries the highest risk of the group, with about a 7 percent chance of a major malformation as monotherapy, compared with roughly 3 percent for carbamazepine or lamotrigine; combining two or more antiseizure drugs raises the risk further, to around 15 percent.
• Being seizure-free for 9 months to a year before conception is linked to a 74 to 92 percent chance of staying seizure-free through pregnancy. Once you're pregnant, the general guidance shifts: medications generally aren't stopped or switched at that point, since that itself raises the risk of poor seizure control, though your dose may still need adjusting as pregnancy changes how your body processes the drug.