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

What You Need to Know About Seizure Medications During Pregnancy

If you’re taking medication for seizures and thinking about getting pregnant, you’re not alone - but you’re also not alone in feeling overwhelmed. The truth is, managing epilepsy during pregnancy is one of the most complex decisions in neurology. You need to keep seizures under control, but you also can’t ignore the risks to your baby. Some seizure medications are far safer than others. Some can mess with birth control. And some, like valproate, carry risks so high that doctors now strongly advise against using them in women who could become pregnant.

Here’s the hard part: stopping your meds isn’t safer. Uncontrolled seizures - especially tonic-clonic ones - can cause miscarriage, premature birth, or even oxygen deprivation to the fetus. The real danger isn’t just the drugs. It’s the balance between two threats: seizures and side effects.

Which Seizure Medications Are Riskiest During Pregnancy?

Not all antiseizure drugs are created equal when it comes to fetal safety. The biggest red flag is valproic acid (also called sodium valproate or Epilim). Decades of research show it’s linked to a 10% risk of major birth defects - nearly five times higher than the general population’s 2-3% baseline. These include heart defects, cleft lip or palate, spinal cord problems like spina bifida, and microcephaly (a smaller-than-normal head size).

Children exposed to valproate in the womb also face higher chances of autism and ADHD. A 2020 study in Neurology found they were more than twice as likely to be diagnosed with autism spectrum disorder compared to kids whose mothers took other seizure drugs. The risk rises with higher doses, and there’s no safe threshold - meaning even low doses carry danger.

Other high-risk medications include:

• Carbamazepine (Tegretol) - linked to neural tube defects and heart problems
• Phenytoin (Epanutin) - can cause fetal hydantoin syndrome, which includes facial abnormalities and growth delays
• Phenobarbital - associated with cognitive delays and physical malformations
• Topiramate (Topamax) - increases risk of cleft lip and low birth weight, especially at doses above 100mg/day

The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) and the Epilepsy Society have both issued clear warnings: these drugs should be avoided in women of childbearing age unless there’s absolutely no alternative. And even then, doctors should use the lowest possible dose.

Which Seizure Medications Are Safer in Pregnancy?

The good news? Not all seizure drugs are dangerous. Two medications stand out as the safest choices for pregnant women: lamotrigine (Lamictal) and levetiracetam (Keppra).

A large 2021 Stanford study tracked 298 children born to mothers who took newer-generation seizure drugs. At age two, their language skills were on par with children whose mothers didn’t take any antiseizure meds. No major increase in birth defects. No signs of developmental delay. That’s a huge shift from the 1980s and 90s, when most women were put on valproate because it worked well.

Lamotrigine and levetiracetam are now the first-line recommendations for women planning pregnancy. They’re effective at controlling seizures and carry minimal risk to the fetus. In fact, the overall rate of major congenital malformations dropped by 39% between 1997 and 2011 - largely because doctors started switching patients to these safer drugs.

Still, even these medications need careful dosing. Lamotrigine levels drop dramatically during pregnancy - sometimes by 50% or more - because your body processes it faster. That means you might need a higher dose as your pregnancy progresses. Without monitoring, you could start having seizures again. That’s why regular blood tests are non-negotiable.

Drug Interactions: Birth Control and Seizure Meds Don’t Mix

Here’s something many women don’t realize: your seizure meds can make your birth control useless. And your birth control can make your seizure meds stop working.

Medications like carbamazepine, phenytoin, phenobarbital, and high-dose topiramate speed up how your liver breaks down hormones. That means the pill, patch, or ring won’t stay in your system long enough to prevent pregnancy. Studies show up to 30% of women on these drugs get pregnant while using hormonal contraception - not because they forgot a pill, but because the meds canceled it out.

The reverse is also true. Hormonal contraceptives lower the blood levels of lamotrigine, valproate, zonisamide, and rufinamide. If you’re on lamotrigine and start the pill, your seizure control can fall apart. One woman in Birmingham told her neurologist she’d had three seizures in a week after starting birth control. Her lamotrigine level had dropped by 60%.

What’s the fix? Non-hormonal options. Copper IUDs are highly effective and don’t interact with any seizure meds. Progestin-only implants (like Nexplanon) are also safe. Some doctors recommend doubling the estrogen dose in pills, but that’s not always reliable. The safest path? Talk to your neurologist and gynecologist together - before you start trying to conceive.

Why Uncontrolled Seizures Are More Dangerous Than Meds

It’s easy to think: "If the drugs are risky, maybe I should just stop them." But that’s where things get deadly.

Every time you have a tonic-clonic seizure during pregnancy, your body goes into crisis mode. Your oxygen levels drop. Your blood pressure spikes. Your uterus contracts. That’s enough to trigger miscarriage, placental abruption, or preterm labor. In extreme cases, the baby can die in the womb.

Dr. Kelsey Wiggs from Indiana University calls this the "excruciating double bind." You can’t win by stopping meds - because seizures are just as dangerous, if not more so. The goal isn’t to avoid all drugs. It’s to pick the right ones and manage them carefully.

The American Epilepsy Society puts it bluntly: "No antiseizure medication is as dangerous as uncontrolled seizures." That’s why doctors now push for preconception planning. If you’re on valproate and thinking about pregnancy, you don’t wait until you’re pregnant to switch. You switch months - sometimes a year - ahead of time.

What to Do If You’re Planning a Pregnancy

Here’s a clear, step-by-step plan if you’re a woman with epilepsy thinking about having a baby:

1. Don’t stop your meds on your own. Stopping suddenly can cause status epilepticus - a life-threatening seizure emergency.
2. See your neurologist at least 6 months before trying to conceive. This isn’t a quick chat. It’s a full medication review.
3. Ask if you’re on valproate, phenobarbital, phenytoin, carbamazepine, or high-dose topiramate. If yes, discuss switching to lamotrigine or levetiracetam.
4. Get your blood levels checked. Lamotrigine and levetiracetam need monitoring every 4-8 weeks during pregnancy.
5. Switch to a non-hormonal birth control method. Copper IUD or implant are best. Avoid pills, patches, or rings if you’re on enzyme-inducing drugs.
6. Start taking 5mg of folic acid daily. This reduces the risk of neural tube defects, even if you’re on a high-risk drug.
7. Plan for regular ultrasounds and prenatal screening. A detailed anomaly scan at 20 weeks can catch many structural problems early.

Many women feel guilty about needing medication during pregnancy. But you’re not choosing between being a good mom and being healthy. You’re choosing how to be both.

What’s Changing - And What Still Needs Work

The landscape has improved dramatically. Ten years ago, nearly half of women with epilepsy were on valproate during pregnancy. Today, that number is below 10% in the UK and US. More doctors are trained in epilepsy and pregnancy care. More women are getting preconception counseling.

But disparities remain. A French study found women with lower income, less education, or limited access to specialists were far more likely to stay on high-risk drugs during pregnancy. That’s not just a medical issue - it’s a justice issue.

There are still 11 antiseizure drugs with unclear safety data during pregnancy. We need more research. We need better tools to predict individual risk. And we need every woman with epilepsy - no matter her background - to have access to the safest care.

Final Thoughts: You Have Options

It’s not about avoiding pregnancy because of epilepsy. It’s about planning it wisely. Thanks to better drugs, better monitoring, and better guidelines, women with epilepsy today have more opportunities than ever to have healthy babies.

The key? Don’t wait. Don’t assume. Don’t guess. Talk to your doctor - early, honestly, and often. Your brain matters. Your baby matters. And with the right plan, you don’t have to choose between them.