Epilepsy Drugs in Pregnancy: Safest Anticonvulsant Options

TL;DR

• Valproate is contraindicated in pregnancy — it carries the highest risk of major congenital malformations (~10%) and neurodevelopmental harm.
• Lamotrigine and levetiracetam are the preferred anticonvulsants in pregnancy, with major malformation rates close to the background population (~2–3%).
• All women of childbearing potential on antiseizure medication should take high-dose folic acid (4–5 mg/day) starting before conception.
• Serum drug levels often fall significantly during pregnancy — monthly therapeutic drug monitoring and dose adjustments are essential.
• Never stop antiseizure medication abruptly; uncontrolled seizures pose serious risks to both mother and fetus.

Why Epilepsy in Pregnancy Requires Special Attention

Epilepsy affects approximately 0.5–1% of women of reproductive age worldwide. For the vast majority, continued antiseizure medication (ASM) throughout pregnancy is medically necessary — uncontrolled generalized tonic-clonic seizures carry risks of maternal trauma, placental abruption, fetal hypoxia, and, rarely, maternal death. The clinical challenge is finding an epilepsy medication safe in pregnancy that controls seizures while minimizing teratogenic exposure.

This is not a theoretical problem. Data from the EURAP International Antiepileptic Drug and Pregnancy Registry — the largest prospective registry of its kind, with over 40,000 pregnancies — have demonstrated that teratogenic risk varies dramatically between individual anticonvulsants, and is often dose-dependent. The right drug choice, ideally made before conception, can reduce the risk of birth defects from over 10% to near-background levels.

The 2024 American Academy of Neurology (AAN) and American Epilepsy Society (AES) practice guidelines, along with recommendations from ACOG, NICE, and the EMA, now provide a clear evidence hierarchy for choosing anticonvulsants in pregnancy. This article summarizes that evidence.

Ranking Anticonvulsants by Teratogenic Risk

Not all antiseizure medications carry equal reproductive risk. The table below ranks commonly prescribed anticonvulsants based on prospective registry data (primarily EURAP and the North American AED Pregnancy Registry) and current guideline recommendations.

Comparative Teratogenic Risk of Antiseizure Medications

Key clinical takeaway: Lamotrigine and levetiracetam stand out as the anticonvulsants with the most reassuring pregnancy safety data. Their major malformation rates approximate the baseline risk in the general population.

Valproate: Understanding Why It Is Contraindicated

Valproate (valproic acid, sodium valproate, divalproex) deserves separate discussion because its reproductive risks are not limited to structural malformations.

Structural teratogenicity. EURAP data consistently show MCM rates of 9–11% with valproate monotherapy, rising to 24% or higher with polytherapy combinations that include valproate, and increasing sharply at doses above 600–700 mg/day. The risk of spina bifida alone is approximately 1–2%, roughly 10–20 times the background rate.

Neurodevelopmental toxicity. The NEAD (Neurodevelopmental Effects of Antiepileptic Drugs) study followed children to age 6 and demonstrated that in utero valproate exposure was associated with an average 7–10 point reduction in IQ compared to lamotrigine, carbamazepine, or phenytoin exposure. Subsequent studies have linked fetal valproate exposure to increased rates of autism spectrum disorder (adjusted risk ratio ~3–5×) and attention deficit/hyperactivity disorder.

Regulatory actions. The FDA, EMA, and MHRA have all issued their strongest warnings against valproate use in pregnancy:

• The EMA mandated a Pregnancy Prevention Programme for all women of childbearing potential on valproate.
• The FDA requires a boxed warning and patient acknowledgment forms.
• NICE guideline NG217 states valproate must not be initiated in female patients of childbearing potential unless other treatments are ineffective or not tolerated, and a pregnancy prevention programme is in place.

When valproate cannot be avoided. In rare cases — particularly certain genetic generalized epilepsies (e.g., juvenile myoclonic epilepsy) where valproate is uniquely effective — the decision requires thorough informed consent, use of the lowest effective dose (ideally <500 mg/day), high-dose folic acid, and detailed fetal ultrasound monitoring. This decision should involve an epileptologist and a maternal-fetal medicine specialist.

Preferred Options: Lamotrigine and Levetiracetam in Detail

Lamotrigine

Lamotrigine is the most extensively studied antiseizure medication in pregnancy, with over 10,000 monotherapy exposures recorded in prospective registries.

• MCM rate: Approximately 2.0–3.2% at typical doses, with no clear dose-response relationship below 300 mg/day. Some data suggest a modest increase above 400 mg/day, but this remains debated.
• No specific malformation pattern has been identified in large datasets.
• Neurodevelopmental outcomes in children exposed in utero appear reassuring, with IQ scores comparable to unexposed controls in the NEAD study.
• Pharmacokinetic challenge: Lamotrigine clearance increases substantially during pregnancy — up to 50–65% by the third trimester — due to enhanced glucuronidation driven by rising estrogen levels. This frequently results in breakthrough seizures if doses are not increased. Clearance returns rapidly to pre-pregnancy levels postpartum, requiring prompt dose reduction to avoid toxicity.

Levetiracetam

Levetiracetam has a growing body of prospective data (>4,000 monotherapy exposures in EURAP) supporting its safety.

• MCM rate: Approximately 2.0–2.8%, comparable to lamotrigine and the background rate.
• No specific malformation pattern identified.
• Neurodevelopmental data are more limited than for lamotrigine but appear reassuring in available studies.
• Pharmacokinetic change: Renal clearance of levetiracetam increases during pregnancy, with serum levels declining by approximately 40–60%. Dose increases are commonly needed, particularly in the second and third trimesters.

Both drugs are endorsed as first-line options in the 2024 AAN/AES guidelines and by NICE, ACOG, and the EMA for women planning pregnancy or who become pregnant on treatment.

Preconception Planning and Folic Acid

The ideal time to optimize antiseizure therapy is before conception. Approximately half of pregnancies are unplanned, which underscores the importance of discussing reproductive intentions with all women of childbearing age who have epilepsy at every clinical encounter.

Preconception checklist

1. Review ASM choice. If the patient is on valproate, phenobarbital, topiramate, or phenytoin, consider switching to lamotrigine or levetiracetam — ideally at least 6 months before conception to ensure seizure stability on the new regimen.
2. Use monotherapy at the lowest effective dose wherever possible. Polytherapy, particularly combinations including valproate, substantially increases malformation risk.
3. Start high-dose folic acid. All major guidelines (AAN/AES, ACOG, NICE, WHO) recommend 4–5 mg/day of folic acid for women on antiseizure medication, beginning at least 1–3 months before conception and continuing through at least the first trimester (many clinicians continue throughout pregnancy). This is approximately 10× the standard prenatal dose and requires a prescription in most countries.
4. Establish baseline serum drug levels to guide monitoring during pregnancy.
5. Counsel the patient that abrupt ASM discontinuation is dangerous and that the risk of uncontrolled seizures generally outweighs medication-related risks.

Why 4–5 mg folic acid, not the usual 0.4 mg? Several anticonvulsants (valproate, carbamazepine, phenytoin, phenobarbital) interfere with folate metabolism. While direct evidence that high-dose supplementation prevents ASM-related neural tube defects is limited, the risk-benefit profile strongly favors supplementation. The AAN/AES and ACOG both endorse this higher dose.

Dose Adjustments and Therapeutic Drug Monitoring During Pregnancy

Pregnancy induces profound pharmacokinetic changes — increased blood volume, enhanced renal clearance, altered hepatic metabolism, and changes in protein binding — that can dramatically affect ASM serum levels.

Recommended Monitoring and Dose Adjustment Strategy

The clinical target is to maintain serum levels at or near the individual's pre-pregnancy baseline — the level at which seizure control was established. A level decline of >35% from baseline is generally considered an indication for dose adjustment, particularly if accompanied by seizure recurrence.

Postpartum. Lamotrigine levels rebound rapidly (within days to weeks) after delivery as estrogen levels fall. Failure to reduce lamotrigine doses promptly postpartum can result in dose-dependent toxicity (dizziness, diplopia, ataxia, rash). A practical approach is to reduce the dose to the pre-pregnancy regimen over 2–3 weeks after delivery, guided by clinical symptoms and serum levels.

Monitoring the Pregnancy: Ultrasound and Screening

All pregnancies exposed to antiseizure medications warrant enhanced fetal surveillance:

• Detailed anatomy scan at 18–22 weeks with particular attention to neural tube, cardiac structures, orofacial clefts, and limb anomalies.
• Early anatomy scan at 14–16 weeks is recommended by some centers for high-risk exposures (valproate, carbamazepine, topiramate).
• First-trimester screening (nuchal translucency plus serum markers) should be offered per standard guidelines.
• Fetal echocardiography should be considered for valproate, phenobarbital, and phenytoin exposures, given increased cardiac malformation rates.
• Serial growth scans in the third trimester are advisable for topiramate exposure (associated with small-for-gestational-age infants) and whenever polytherapy is used.

Labour, Delivery, and the Postpartum Period

During labour

• Continue ASM throughout labour. If oral administration is not possible, intravenous levetiracetam or (for those on phenytoin) intravenous phenytoin/fosphenytoin can be used. There is no widely available parenteral formulation of lamotrigine.
• Seizure first aid equipment and intravenous benzodiazepine access should be available in the delivery room.
• Epilepsy alone is not an indication for caesarean section — vaginal delivery is appropriate for most women with epilepsy.

Breastfeeding

All first-line ASMs are considered compatible with breastfeeding per LactMed and AAP guidance:

• Lamotrigine passes into breast milk (relative infant dose ~9–18%), and infant serum levels can reach 20–50% of maternal levels. Clinically significant effects are rare, but monitoring the infant for sedation, poor feeding, or rash is recommended, particularly in the neonatal period.
• Levetiracetam transfers into breast milk in modest amounts. Infant exposure is generally low, and no adverse effects have been reported in published case series.
• Valproate has low breast-milk transfer (relative infant dose ~1–6%) and is considered compatible with breastfeeding, despite its teratogenic profile — teratogenicity is an in utero phenomenon, not a lactation concern.
• Carbamazepine is generally compatible, though rare cases of neonatal hepatic dysfunction have been reported; monitor the infant clinically.

The benefits of breastfeeding generally outweigh ASM-related risks for all commonly used anticonvulsants. Women should be encouraged to breastfeed unless there are other contraindications.

Postpartum dose adjustment

As noted above, lamotrigine requires prompt dose reduction postpartum. Levetiracetam doses should also be tapered back toward pre-pregnancy levels, though the rebound is less acute. Sleep deprivation is a potent seizure trigger — postpartum seizure risk management should include counselling on sleep hygiene and shared nighttime infant care.

Vitamin K and the Newborn

Older enzyme-inducing ASMs (phenobarbital, phenytoin, carbamazepine) can reduce neonatal vitamin K–dependent clotting factors, theoretically increasing haemorrhagic disease risk. Standard practice is to administer vitamin K 1 mg intramuscularly to all neonates at birth (per WHO and AAP recommendations); this is sufficient for infants of mothers on ASMs. Some guidelines previously recommended maternal oral vitamin K supplementation (10–20 mg/day) in the final month of pregnancy for those on enzyme-inducers, but this practice is no longer universally endorsed. Discuss with the delivering obstetric team.

Red Flags — When to Seek Urgent Medical Attention

Pregnant women with epilepsy should be counselled to seek immediate medical care if:

• Any seizure occurs during pregnancy, particularly generalized tonic-clonic seizures
• Signs of status epilepticus — a seizure lasting more than 5 minutes, or repeated seizures without recovery between them
• Vaginal bleeding, abdominal pain, or reduced fetal movement after a seizure (may indicate placental abruption)
• Rash, fever, or mouth ulcers while taking lamotrigine — may indicate Stevens-Johnson syndrome (rare but serious)
• Signs of medication toxicity — severe dizziness, double vision, unsteadiness, vomiting
• Severe headache, visual changes, or facial swelling in the third trimester — these suggest preeclampsia, which must be distinguished from seizures of epilepsy

Frequently Asked Questions

Q: Can I stop my epilepsy medication if I find out I'm pregnant? A: No — never stop antiseizure medication abruptly without medical guidance. Sudden withdrawal can trigger seizure clusters or status epilepticus, which are far more dangerous to both you and your baby than the medication itself. Contact your neurologist immediately to discuss your options.

Q: I'm on valproate and just found out I'm pregnant. What should I do? A: Contact your neurologist urgently. Switching medication during an established pregnancy is not always straightforward — the period of highest teratogenic risk (neural tube closure) is weeks 3–4 post-conception, often before pregnancy is recognized. Your specialist may recommend a carefully supervised transition, but this must be individualized. Do not adjust doses on your own.

Q: Is lamotrigine or levetiracetam better for pregnancy? A: Both have similarly reassuring safety profiles. Lamotrigine has a larger evidence base (more registry exposures and longer-term neurodevelopmental follow-up data), but levetiracetam is equally endorsed by current guidelines. The best drug is the one that controls your seizure type effectively. Switching purely for pregnancy to a drug that may not control your seizures is counterproductive.

Q: Will my baby need extra tests after birth? A: Neonates exposed to ASMs should be observed for signs of sedation, poor feeding, or withdrawal symptoms (irritability, tremor, poor tone), particularly in the first 24–48 hours. Standard newborn screening and vitamin K administration apply. No routine blood-level monitoring of the infant is needed unless clinical concerns arise.

Q: Does epilepsy itself increase the risk of birth defects? A: The evidence suggests that epilepsy per se does not significantly increase the baseline rate of major malformations; the excess risk is primarily attributable to ASM exposure. However, uncontrolled generalized tonic-clonic seizures during pregnancy can cause fetal injury, hypoxia, and adverse obstetric outcomes that are potentially more serious than the medication risk.

Q: Can I take standard-dose folic acid (0.4 mg) instead of 4–5 mg? A: Standard-dose folic acid is better than none, but guidelines specifically recommend 4–5 mg daily for women on antiseizure medications. Several ASMs interfere with folate metabolism, and higher doses are needed to compensate. You will need a prescription for the higher dose.

Q: Is it safe to take two antiseizure medications during pregnancy? A: Polytherapy carries a higher malformation risk than monotherapy, particularly when valproate is one of the drugs. However, if monotherapy does not control seizures, the risk of uncontrolled seizures may outweigh the additional teratogenic risk. This decision must be individualized with your epileptologist. Where polytherapy is necessary, combinations of lamotrigine and levetiracetam are considered among the lower-risk pairings based on limited available data.

References

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2. Meador KJ, Baker GA, Browning N, et al. Cognitive function at 3 years of age after fetal exposure to antiepileptic drugs. N Engl J Med. 2009;360(16):1597–1605. PMID: 19369666

3. NICE. Epilepsies in children, young people and adults. Guideline NG217. 2022 (updated 2024). nice.org.uk/guidance/ng217

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7. Meador KJ, Baker GA, Browning N, et al. Fetal antiepileptic drug exposure and cognitive outcomes at age 6 years (NEAD study). Lancet Neurol. 2013;12(3):244–252. PMID: 23352199

8. Tomson T, Battino D, Bromley R, et al. Management of epilepsy in pregnancy: a report from the International League Against Epilepsy Task Force on Women and Pregnancy. Epileptic Disord. 2019;21(6):497–517. PMID: 31804910

9. ACOG. Practice Bulletin No. 231: Epilepsy in pregnancy. Obstet Gynecol. 2021;137(6):e154–e170. acog.org/clinical/clinical-guidance/practice-bulletin

10. National Library of Medicine. LactMed: Drugs and Lactation Database. ncbi.nlm.nih.gov/books/NBK501922

About the Author

Dr. Stanislav Ozarchuk, PharmD, is a clinical pharmacist with 15 years of experience in drug safety evaluation, pharmacotherapy optimization, and patient education. He has worked across hospital, community, and academic settings with a particular interest in medication use during pregnancy and lactation. Dr. Ozarchuk writes for PillsCard.com, where he translates complex pharmaceutical evidence into accessible, clinically accurate guidance for patients and healthcare professionals worldwide.

Medical Disclaimer

This article is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. The information presented reflects current evidence and guideline recommendations at the time of writing but may not apply to individual clinical circumstances. Do not start, stop, or change any medication — including antiseizure drugs — without consulting your prescribing physician or specialist. Epilepsy management in pregnancy requires individualized care from a multidisciplinary team including a neurologist or epileptologist, obstetrician, and pharmacist. If you are pregnant or planning pregnancy and taking antiseizure medication, seek prompt specialist guidance. PillsCard.com and its authors assume no liability for actions taken based on this content.