Seizure Medications and Pregnancy: Birth Defect Risks and Drug Interactions You Need to Know

When you’re taking medicine to control seizures, planning a pregnancy shouldn’t mean giving up your health-or your dreams of becoming a parent. But it does mean knowing the real risks. Not all seizure medications are the same when it comes to pregnancy. Some carry a clear danger to your baby’s development. Others are much safer. And if you’re also using birth control, there’s another layer: your seizure meds might be making your contraception less effective. This isn’t theoretical. It’s happening right now to thousands of women worldwide.

Some Seizure Medications Are Much Riskier Than Others

Not all antiseizure drugs (ASMs) are created equal when it comes to pregnancy. The biggest red flag is valproate-also known as sodium valproate or valproic acid. Decades of research show it’s linked to serious birth defects in about 10% of pregnancies where it’s taken. That’s five times higher than the general population’s risk of major birth abnormalities, which is around 2-3%. Babies exposed to valproate in the womb are more likely to have heart defects, cleft lips or palates, spinal problems, and microcephaly (a smaller-than-normal head size). They’re also at significantly higher risk for autism and ADHD later in life.

Other high-risk medications include carbamazepine, phenobarbital, phenytoin, and topiramate. These carry lower-but still meaningful-risks. For example, carbamazepine’s risk of birth defects increases with higher doses. Topiramate has been tied to cleft lip and low birth weight. The pattern is clear: older drugs, especially those developed before the 1990s, tend to be more dangerous. Newer ones? Much better.

That’s where lamotrigine and levetiracetam come in. These are now considered the safest options for women who need seizure control during pregnancy. Studies tracking over 298 children exposed to these drugs before birth found no major delays in language development at age two. Their risk of birth defects is close to that of the general population. If you’re planning to get pregnant, switching to one of these two (under medical supervision) can make a huge difference.

What Kind of Birth Defects Are We Talking About?

The risks aren’t vague. They’re specific and measurable. Here’s what the data shows:

• Heart defects: Occur in 1-2% of babies exposed to high-risk ASMs like valproate or phenytoin.
• Cleft lip or palate: Seen in up to 2% of pregnancies with topiramate or phenytoin exposure.
• Neural tube defects: Problems with brain or spinal cord development. Valproate raises this risk by 10-20 times compared to no exposure.
• Microcephaly: A head size smaller than normal. Happens in 0.5-1% of valproate-exposed babies.
• Slow growth and developmental delays: Babies may be born smaller and have trouble reaching milestones like sitting, crawling, or talking.
• Urinary tract problems: Less common, but documented in multiple studies.

It’s important to remember: over 90% of babies born to women with epilepsy are healthy. The risks are real, but they’re not guaranteed. That’s why the goal isn’t to avoid medication entirely-it’s to choose the safest one at the lowest effective dose.

Drug Interactions Can Put You at Risk, Too

If you’re using hormonal birth control-pills, patches, or rings-you might be at risk for an unexpected pregnancy. Why? Because some seizure medications make birth control less effective. The same drugs that are dangerous in pregnancy also interfere with how your body processes hormones.

Medications like carbamazepine, phenytoin, phenobarbital, oxcarbazepine, and high doses of topiramate can speed up how fast your liver breaks down estrogen and progesterone. That means your birth control stops working as well as it should. One study found that nearly 70% of women of childbearing age didn’t know this was happening.

And it works the other way, too. Birth control pills can lower the levels of some seizure drugs in your blood. That includes lamotrigine, valproate, zonisamide, and rufinamide. If your lamotrigine level drops too low, you could start having seizures again. That’s dangerous-for you and your baby.

This isn’t just a footnote. It’s a critical part of your care. If you’re on any of these drugs and using hormonal contraception, you need to talk to your doctor. You might need a higher-dose pill, an IUD, or a non-hormonal option like a copper IUD or condoms with spermicide. Don’t guess. Get tested.

Uncontrolled Seizures Are Just as Dangerous

Here’s the hard truth: stopping your seizure meds because you’re scared of birth defects can be more dangerous than taking them. Tonic-clonic seizures-those full-body convulsions-can cause miscarriage, premature birth, or even oxygen deprivation to the fetus. A fall during a seizure can lead to serious injury. The stress on your body can trigger complications like preeclampsia or placental abruption.

Doctors call this the "excruciating double bind." You need the medication to stay safe. But the medication might hurt your baby. The solution isn’t to pick one side. It’s to find the best balance. That’s why experts from the American Epilepsy Society say: no seizure medication is as dangerous to a pregnant woman and her baby as uncontrolled seizures.

The goal isn’t to be seizure-free at all costs. It’s to be seizure-controlled with the safest possible drug. That’s why preconception counseling is non-negotiable. If you’re thinking about getting pregnant-or even just sexually active-you need to talk to your neurologist before you stop using birth control.

Progress Is Real-But Not Everyone Is Getting It

There’s good news. Between 1997 and 2011, the rate of major birth defects linked to seizure medications dropped by 39%. Why? Because doctors started prescribing safer drugs like lamotrigine and levetiracetam instead of valproate. More women are getting counseling before pregnancy. More are switching to safer options.

But progress isn’t equal. A French study found that women with lower income, less education, or limited access to healthcare were far more likely to be prescribed high-risk drugs like valproate during pregnancy. They were less likely to get preconception advice. They were more likely to be on multiple medications. That’s not just a medical issue-it’s a social justice issue.

Even today, some doctors still default to older, cheaper drugs. Some patients don’t know they have a choice. If you’re on valproate or phenobarbital and you’re planning a pregnancy-or could become pregnant-you need to ask: "Is there a safer option?" Don’t wait for your doctor to bring it up. Be the one to start the conversation.

What Should You Do Now?

If you’re taking any seizure medication and you’re of childbearing age, here’s what to do:

1. Don’t stop your meds. Sudden withdrawal can cause life-threatening seizures.
2. Ask your neurologist: "Which of my medications are safest for pregnancy?" If you’re on valproate, ask if switching to lamotrigine or levetiracetam is possible.
3. Get a blood test. Levels of lamotrigine, valproate, and other drugs can drop during pregnancy. Monitoring is key.
4. Review your birth control. If you’re on hormonal contraception, ask if your seizure meds are reducing its effectiveness. Consider a copper IUD if you’re not planning pregnancy soon.
5. Plan ahead. If you’re thinking about pregnancy, schedule a preconception visit at least 3-6 months in advance. That’s how long it takes to safely switch medications.

There’s no perfect answer. But there is a better path. You don’t have to choose between being healthy and having a child. You just need the right information-and the right care team.

What About the Future?

Researchers are still studying 11 other seizure medications because there’s not enough data yet to say if they’re safe in pregnancy. That means even if you’re on a "newer" drug, you might not know the full picture. Ongoing studies are tracking children exposed to these drugs from birth through adolescence. The goal? To build a clearer, safer roadmap for every woman with epilepsy.

One thing’s certain: the future of epilepsy care in pregnancy is brighter than it was 20 years ago. Women today have more options, better data, and more support. You’re not alone. And you don’t have to accept outdated advice.