Anti-seizure medications (ASMs) are essential, life-saving therapies for millions of people. They help control seizures, improve safety, and improve quality of life.

For women able to become pregnant between the ages of 13 and 51 who take at least one anti-seizure medication, there is an important and often under-emphasized component of preventive care: folic acid supplementation.

Folic acid is a B vitamin (vitamin B9) that plays a critical role in DNA synthesis, red blood cell formation, and nervous system development. Adequate folic acid intake is key for women of reproductive age. When anti-seizure medications are taken, supplementation becomes even more important—not only for pregnancy-related outcomes, but for overall health.

The Role of Folic Acid in the Body

Folic acid is the synthetic form of folate, a vitamin naturally found in leafy green vegetables, legumes, and fortified grains. Folate is essential for cell division and growth, particularly during periods of rapid development such as adolescence and early pregnancy. Deficiency can lead to megaloblastic anemia, fatigue, cognitive difficulties, and elevated homocysteine levels, which are associated with cardiovascular risk (Bailey et al., 2015).

During early pregnancy, folate is crucial for proper closure of a developing baby’s neural tube, which forms the brain and spinal cord. Inadequate folate during the first four weeks of pregnancy significantly increases the risk of neural tube defects, such as spina bifida and anencephaly (CDC, 2023).

How Anti-Seizure Medications Affect Folate Levels

Many anti-seizure medications interfere with the body’s ability to process folate. Some reduce intestinal absorption, while others increase its metabolism in the liver or interfere with folate-dependent enzymatic pathways. Older ASMs such as valproate, carbamazepine, phenytoin, phenobarbital, and primidone have been most strongly linked to reduced folate levels, though supplementation is recommended broadly for women taking any ASM (Harden et al., 2009).

Women taking anti-seizure medications are at higher risk for folate deficiency—even when consuming a folate-rich diet. This interaction between medication and this vital nutrient is a key reason folic acid supplementation is recommended, rather than relying on dietary intake alone.

Pregnancy, Anti-Seizure Medications, and Birth Defect Risk

Women of child-bearing potential who have epilepsy face unique reproductive health considerations. Certain anti-seizure medications have been associated with increased risks of congenital malformations, including neural tube defects, cardiac anomalies, and orofacial clefts. Valproate has been consistently linked to higher rates of neural tube defects and adverse neurodevelopmental outcomes (Tomson et al., 2018).

While folic acid supplementation does not eliminate all medication-related risks, substantial evidence suggests that getting enough folic acid reduces the risk of neural tube defects (such as spina bifida) and may improve brain function and development in children exposed to ASMs while in the uterus (Meador et al., 2013; AAN, 2009).

Because neural tube development occurs very early—often before pregnancy is recognized—folic acid must be taken consistently before conception. This is especially important given that nearly half of all pregnancies in the United States are unplanned (CDC, 2022).

Why Supplementation Is Recommended Starting at Age 12

Public health guidelines strongly recommend folic acid supplements for all women of reproductive age, beginning in adolescence. Puberty marks the onset of reproductive capability, and anti-seizure medications are frequently prescribed during childhood or adolescence for epilepsy and other neurologic conditions.

Starting folic acid supplementation early helps ensure adequate folate levels long before pregnancy. It also supports normal growth, hematologic health, and neurologic function during adolescence—critical developmental years when nutritional needs are high.

Benefits of Folic Acid Beyond Pregnancy

Although prevention of birth defects is often the focus, folic acid offers broader health benefits throughout the reproductive lifespan. Adequate folate levels help:

· Prevent folate-deficiency anemia

· Support cognitive and neurologic function

· Reduce elevated homocysteine levels associated with cardiovascular risk

· Support overall cellular health and energy levels

For women managing chronic seizure disorders, meeting nutritional needs is an important component of long-term health and quality of life.

Recommended Folic Acid Dosing for Women on Anti-Seizure Medications

For most women of childbearing age, health authorities recommend at least 0.4 mg (400 micrograms) of folic acid daily (CDC, 2023). However, women taking anti-seizure medications are often advised to take higher doses, commonly 1 mg daily, with some individuals prescribed even higher amounts depending on medication type, seizure control, and pregnancy plans (ACOG, 2024; Harden et al., 2009).

Folic acid is inexpensive, widely available, and generally safe. Nevertheless, dosing should be discussed with a healthcare provider—such as a neurologist, primary care clinician, or obstetric provider—to ensure appropriate individualized care.

Addressing Common Misconceptions

A frequent misconception is that folic acid is only necessary when actively planning a pregnancy. Pregnancy may occur unexpectedly, and because ASMs can lower folate levels over time, routine supplementation is recommended regardless of pregnancy intention.

Another misconception is that fortified foods alone provide sufficient folate. While dietary folate is important, medication-related interference makes supplementation necessary for many women taking ASMs.

A Simple, Evidence-Based Preventive Measure

For women ages 13 to 51 who take at least one ASM, folic acid supplementation is a simple but powerful preventive strategy. It supports general health, reduces the risk of serious birth defects, and helps the body maintain folate levels that may be lowered by medication.

Healthcare providers play a critical role in counseling patients, but awareness among patients, families, educators, and advocates is equally important. Asking about folic acid, understanding its benefits, and taking it consistently can have lifelong implications.

In the management of epilepsy and seizure disorders, medication therapy is essential—but so is comprehensive, proactive care. Folic acid supplementation represents one of the most effective, proven ways to support the present and future health of women living with seizure disorders.

For more information or questions, please contact us at the WVU Medicine Golisano Children’s Comprehensive Epilepsy Center at 855-988-2273 or 304-598-4835.

References

1. American Academy of Neurology (AAN). (2009). Practice parameter update: Management issues for women with epilepsy—Focus on pregnancy. Neurology, 73(2), 133–141.
2. American College of Obstetricians and Gynecologists (ACOG). (2024). Epilepsy and pregnancy. ACOG Practice Bulletin.
3. Bailey, L. B., et al. (2015). Folate status in the US population. American Journal of Clinical Nutrition, 101(6), 1319S–1326S.
4. Centers for Disease Control and Prevention (CDC). (2022). Unintended pregnancy in the United States.
5. Centers for Disease Control and Prevention (CDC). (2023). Folic acid: Recommendations and benefits.
6. Harden, C. L., et al. (2009). Management issues for women with epilepsy—Focus on pregnancy. Epilepsia, 50(5), 1237–1246.
7. Meador, K. J., et al. (2013). Fetal antiepileptic drug exposure and cognitive outcomes at age 6 years. New England Journal of Medicine, 360(16), 1597–1605.
8. Tomson, T., et al. (2018). Valproate exposure and neurodevelopmental outcomes. The Lancet Neurology, 17(6), 530–538.