Seizure Medications and Pregnancy: Risks of Birth Defects and Drug Interactions

When you’re taking medication to control seizures, and you’re thinking about having a baby, the questions don’t stop at "Will this work?" They get heavier: Will this drug hurt my baby? Could my birth control fail because of my seizure meds? Is there a safer option? The truth is, there’s no simple answer - but there is clear, up-to-date guidance that can help you make smarter choices.

Some Seizure Medications Carry Real Risks During Pregnancy

Not all antiseizure medications (ASMs) are created equal when it comes to pregnancy. The biggest red flag has long been sodium valproate. If you take this drug while pregnant, your baby has about a 10% chance of being born with a major physical birth defect - things like heart problems, cleft lip or palate, or spinal cord issues. That’s more than double the risk seen with most other seizure drugs. And it’s not just physical. Children exposed to valproate in the womb are more than twice as likely to be diagnosed with autism or ADHD later on, according to a major 2020 study in Neurology.

Other high-risk drugs include carbamazepine, phenobarbital, phenytoin, and topiramate. These also raise the chance of birth defects, especially at higher doses. The risks aren’t just theoretical - they’re documented in thousands of pregnancies tracked over decades. Still, it’s important to remember: over 90% of babies born to mothers with epilepsy are healthy. That means the risks, while serious, are not guaranteed.

Safer Alternatives Exist - And They’re Widely Available

The good news? Two medications have consistently shown much lower risks during pregnancy: lamotrigine (Lamictal) and levetiracetam (Keppra). A 2023 review by the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) confirmed these two as the safest options currently available. Studies tracking children born to mothers taking lamotrigine or levetiracetam found normal development in language, motor skills, and cognitive function by age two. One Stanford study of 298 children found no significant difference in verbal abilities compared to children whose mothers didn’t take any seizure meds.

That’s a huge shift from the past. In the 1960s and 70s, women with epilepsy were often told not to have children at all. Today, thanks to better research and safer drugs, most women with epilepsy can have healthy pregnancies - as long as they’re on the right medication. The key is switching to a safer drug before getting pregnant. Stopping or changing meds mid-pregnancy can be dangerous because uncontrolled seizures carry their own risks - including miscarriage, injury, or oxygen deprivation to the baby.

Drug Interactions Can Sabotage Both Birth Control and Seizure Control

Here’s something many people don’t realize: your seizure medication can interfere with your birth control - and vice versa. Drugs like carbamazepine, phenytoin, phenobarbital, and high-dose topiramate speed up how your body breaks down hormones. That means birth control pills, patches, or rings might not work as well. One study found that nearly two-thirds of women of childbearing age with epilepsy answered basic questions about these interactions incorrectly.

And it goes both ways. Hormonal birth control can lower the levels of some seizure drugs in your blood. That’s especially true for lamotrigine, valproate, zonisamide, and rufinamide. If your lamotrigine level drops too low, you could start having seizures again - even if you’ve been stable for years. That’s why women on these drugs often need higher doses of birth control or alternative methods like IUDs or implants, which aren’t affected by liver enzymes.

Uncontrolled Seizures Are More Dangerous Than Most Medications

It’s easy to focus only on the risks of the drugs. But the bigger risk? Not taking them. A single tonic-clonic seizure during pregnancy can cause oxygen loss, falls, trauma, or even fetal death. That’s why experts agree: no ASM is as dangerous as uncontrolled seizures. The goal isn’t to stop all meds - it’s to find the safest one that still works.

Neurologists call this the "excruciating double bind." You need the drug to stay safe, but you fear it might hurt your baby. The solution isn’t to choose one over the other - it’s to plan ahead. Talk to your neurologist and OB-GYN before you even try to conceive. Bring a list of every medication you take, including over-the-counter supplements. Ask: "Is this the safest option for pregnancy?" and "Do I need to adjust my birth control?"

Why Some Women Still Get High-Risk Medications

If safer options exist, why are some women still prescribed valproate or phenobarbital during pregnancy? One reason: lack of access. A French study found that women with lower income or fewer healthcare resources were more likely to be on high-risk drugs. Sometimes it’s because their neurologist didn’t know the latest guidelines. Other times, they couldn’t get a referral to a specialist, or their insurance wouldn’t cover the newer, pricier drugs.

Another reason: seizure control. Some women have tried lamotrigine or levetiracetam before and didn’t respond well. In those cases, doctors may have to weigh the risks differently. But even then, the dose should be kept as low as possible. Research shows that higher doses of carbamazepine, phenobarbital, and valproate directly increase the chance of birth defects. Lowering the dose - even if it means more frequent seizures - can reduce fetal risk.

What Has Improved Over Time

There’s real progress. Between 1997 and 2011, the rate of major birth defects in babies exposed to ASMs dropped by 39%. Why? Because doctors stopped prescribing valproate as a first-line treatment. They started using lamotrigine and levetiracetam more often. They began recommending preconception counseling. And they started testing drug levels during pregnancy to make sure doses stayed effective.

Today, guidelines from the American Epilepsy Society and the NIH are clear: women with epilepsy who are planning pregnancy should avoid valproate unless there’s no other option. If you’re on it now and thinking of having a baby, don’t stop cold turkey. Talk to your doctor. There’s a safe way to switch.

What’s Still Unknown

There are 11 other antiseizure drugs that still don’t have enough data to say whether they’re safe in pregnancy. That includes newer ones like cenobamate, eslicarbazepine, and perampanel. Researchers are still tracking outcomes in children exposed to these drugs. Until we know more, the safest bet is to stick with lamotrigine or levetiracetam - unless your situation demands something else.

What You Can Do Right Now

• If you’re on valproate and could get pregnant: schedule a conversation with your neurologist now. Don’t wait.
• If you’re on carbamazepine, phenytoin, phenobarbital, or topiramate: ask if switching to lamotrigine or levetiracetam is possible.
• If you’re on lamotrigine and use hormonal birth control: get your blood levels checked. You may need a higher dose of birth control or a non-hormonal method.
• If you’re not on birth control and sexually active: talk to your doctor about which methods are safest with your meds.
• If you’re planning pregnancy: ask for a preconception epilepsy consultation. It’s not a luxury - it’s standard care.

Having epilepsy doesn’t mean you can’t have a healthy baby. It means you need a better plan. The tools to make that happen are here. You just need to use them.