Researchers studied how a vital nutrient called folate gets to babies during pregnancy in women taking seizure medications. They found that seizure drugs may interfere with how folate moves from mother to baby through the placenta. In 51 pregnant women (22 with epilepsy on medication, 10 with untreated epilepsy, and 19 without epilepsy), scientists measured folate levels in mother’s blood and umbilical cord blood at birth. The study suggests that women with epilepsy taking seizure medications may need extra folate supplements and careful monitoring to ensure their babies get enough of this important nutrient for healthy development.

The Quick Take

  • What they studied: Whether seizure medications prevent folate (a B vitamin) from reaching babies in the womb, and what factors affect how much folate babies receive
  • Who participated: 51 pregnant women at two hospitals: 22 women with epilepsy taking seizure medications, 10 women with epilepsy not taking medications, and 19 women without epilepsy. All were studied at the time of delivery.
  • Key finding: Seizure medications appear to interfere with folate transfer to the baby. Mothers taking seizure drugs had lower folate delivery to their babies compared to mothers without epilepsy, even when mother’s blood folate levels looked normal.
  • What it means for you: If you have epilepsy and take seizure medications while pregnant, you should discuss folate supplementation with your doctor and have your folate levels checked regularly. This doesn’t mean you should stop your seizure medication—seizures during pregnancy are dangerous—but your doctor may recommend extra folate to protect your baby’s development.

The Research Details

This was a cross-sectional study, which means researchers collected information from all participants at one point in time (at delivery). They compared three groups of pregnant women: those with epilepsy taking seizure medications, those with epilepsy not taking medications, and those without epilepsy. Blood samples were taken from the mother’s vein and from the umbilical cord at birth to measure folate levels. The researchers also measured how much seizure medication was in the blood to see if there was a connection.

The study was conducted at two different hospitals, which helps confirm that results aren’t unique to just one location. All participants had their blood tested using the same reliable laboratory method to measure folate, ensuring accurate comparisons between groups.

This approach allowed researchers to see real-world patterns in how folate reaches babies in different situations, though it couldn’t prove cause-and-effect relationships the way a controlled experiment could.

Understanding how seizure medications affect folate transfer is important because folate is essential for a baby’s brain and spinal cord development. If seizure medications block folate from reaching the baby, doctors need to know this so they can adjust supplementation plans. This study helps explain why simply checking a mother’s blood folate level might not be enough—the baby might not be getting what they need even if the mother’s levels look normal.

This study has some strengths: it measured folate using a validated, accurate laboratory method, included a control group without epilepsy for comparison, and studied participants at two different centers. However, the sample size is relatively small (51 women total), which means results should be confirmed with larger studies. The study only looked at one moment in time (at birth) rather than following women throughout pregnancy, so we don’t know how folate transfer changes over time. The researchers were careful to note these limitations.

What the Results Show

The main finding was that folate transfer to babies appears to work differently in women taking seizure medications. In women without epilepsy, folate levels in the mother’s blood were a good predictor of how much folate the baby would receive. However, in women with epilepsy taking seizure medications, this relationship was weaker, suggesting the medications interfere with the normal transfer process.

When researchers excluded babies born early (preterm), they could predict baby folate levels much better from mother’s blood levels (78% accuracy). This suggests that the timing of delivery matters and that the folate transfer system may have limits in how much it can deliver, especially when seizure medications are involved.

The study found that folate delivery to the fetus during late pregnancy is primarily controlled by how much folate is in the mother’s blood, but in women with epilepsy, this system may have a maximum capacity—like a water pipe that can only deliver so much water no matter how much pressure is applied.

The study noted that women in the control group (without epilepsy) had more cesarean sections, though this difference wasn’t statistically significant. Most other characteristics between groups—like maternal age, baby weight, and delivery timing—were similar. The researchers measured seizure medication levels in both mother and baby blood to understand the relationship between medication exposure and folate transfer, though specific details about this relationship weren’t highlighted as a main finding.

Previous research suggested that seizure medications might interfere with folate, but this study provides direct evidence by measuring folate in both mother and baby blood at the same time. The findings support earlier concerns that checking only the mother’s folate level may not accurately reflect what the baby is receiving. This study adds important information to help doctors better manage folate supplementation in pregnant women with epilepsy.

The study included only 51 women, which is a relatively small number. Larger studies would provide more confidence in the results. The study only looked at folate levels at one moment—at birth—so we don’t know how folate transfer changes throughout pregnancy. The study couldn’t prove that seizure medications directly cause lower folate transfer, only that the pattern appears different. Some women had preterm births, which affected the results, suggesting future studies should focus on full-term pregnancies. Finally, the study didn’t measure all possible factors that might affect folate transfer, such as diet or other medications.

The Bottom Line

Women with epilepsy who are pregnant or planning pregnancy should: (1) Discuss folate supplementation with their neurologist and obstetrician—higher doses may be needed than standard prenatal vitamins; (2) Have folate levels checked regularly throughout pregnancy, not just once; (3) Continue taking seizure medications as prescribed, since stopping them poses serious risks; (4) Eat folate-rich foods like leafy greens, beans, and fortified grains. These recommendations are based on moderate evidence and should be personalized with your healthcare team.

This research is most relevant for women with epilepsy who are pregnant or planning pregnancy, their doctors, and anyone counseling women about pregnancy with epilepsy. Women without epilepsy don’t need to change their folate approach based on this study. Men with epilepsy don’t need to change anything, though this research doesn’t affect them. Healthcare providers should use this information to improve folate monitoring and supplementation strategies for pregnant patients with epilepsy.

Folate works throughout pregnancy to support baby development, so supplementation should ideally start before pregnancy or as soon as pregnancy is confirmed. Benefits of adequate folate accumulate over the entire pregnancy, with the most critical period being the first trimester when the baby’s brain and spinal cord are forming. You won’t see obvious changes, but adequate folate reduces the risk of birth defects. Folate levels in blood can change within weeks of starting supplementation, so your doctor can check if your dose is working after 4-6 weeks.

Want to Apply This Research?

  • Track daily folate supplementation dose and timing, plus record folate blood test results when available. Note which seizure medications you’re taking and any changes to dosages, as this may affect folate needs.
  • Set a daily reminder to take your folate supplement at the same time each day (such as with breakfast). Log when you eat folate-rich foods like spinach, broccoli, lentils, or fortified cereals to ensure you’re getting folate from multiple sources.
  • Schedule folate blood tests every 8-12 weeks during pregnancy (or as recommended by your doctor) and log the results in the app. Track any symptoms of folate deficiency like fatigue or weakness. Create a checklist for prenatal appointments to remind you to discuss folate levels with your healthcare provider at each visit.

This research summary is for educational purposes only and should not replace professional medical advice. If you have epilepsy and are pregnant or planning pregnancy, consult with both your neurologist and obstetrician before making any changes to your medications or supplements. Never stop taking seizure medications without medical supervision, as uncontrolled seizures during pregnancy pose serious risks to both mother and baby. Individual folate needs vary based on your specific medications, health status, and other factors. Your healthcare provider can determine the appropriate folate supplementation and monitoring plan for your situation.