Pregnancy can bring an important balancing act for women living with epilepsy: controlling seizures while choosing the safest possible treatment for the developing baby. New research from the international EURAP pregnancy registry adds another concern to that discussion—fetal growth.
The September 2026 Lancet Neurology study analyzed nearly 15,900 offspring exposed to antiseizure medicines during pregnancy and found that fetal growth outcomes varied by medicine and treatment combination. Polytherapy was associated with a higher risk of small-for-gestational-age (SGA) birth than monotherapy.
Importantly, these findings do not mean that pregnant women should stop antiseizure medicines. Uncontrolled seizures can also put both mother and baby at risk. Treatment decisions should be individualized with an epilepsy specialist and obstetric team.
What Is Poor Fetal Growth?
Poor fetal growth means that a baby is smaller than expected for its gestational age. Researchers commonly assess this using birthweight centiles and measures such as SGA, which generally refers to birthweight below the 10th percentile for gestational age.
The condition can increase the risk of complications around birth and may have implications for longer-term health.
What Did the New Study Find?
The EURAP study followed pregnancies recorded between 1999 and 2023 and assessed several fetal-growth outcomes.
Among the key findings:
- 15,893 offspring were included in the primary analysis.
- 12,911 were exposed to antiseizure medication monotherapy.
- 2,982 were exposed to polytherapy.
- Polytherapy was associated with about a 48% higher adjusted odds of SGA compared with monotherapy.
- Increasing numbers of concomitant antiseizure medicines were associated with lower birthweight centiles.
This is an observational study, so the findings show associations rather than proof that a particular medicine directly caused poor fetal growth.
Which Medicines Were Associated With Lower Birthweight?
The researchers found differences between individual monotherapies.
Compared with lamotrigine, lower adjusted birthweight centiles were observed with:
| Antiseizure medicine | Adjusted difference in birthweight centile* |
|---|---|
| Topiramate | −11.93 |
| Phenobarbital | −8.08 |
| Oxcarbazepine | −5.10 |
| Carbamazepine | −3.15 |
| Valproic acid | −2.54 |
| Levetiracetam | −2.51 |
*Adjusted coefficients reported by the study; these are not percentages of babies affected. (ScienceDirect)
Topiramate showed the largest difference among the monotherapies studied, but individual treatment decisions cannot be based on fetal growth alone.
Does Polytherapy Increase the Risk?
The study found a higher risk of poor fetal growth with polytherapy than with monotherapy.
The adjusted odds of SGA were approximately 1.48 times higher with polytherapy. Severe SGA and low birthweight were also more common in the polytherapy group.
However, people who require several medicines may have more difficult-to-control epilepsy, so the underlying severity of epilepsy and other health factors can also influence pregnancy outcomes.
Why Can’t Women Simply Stop Their Medication?
This is one of the most important points.
Stopping antiseizure medication without medical supervision can be dangerous. Seizures during pregnancy may cause injury, oxygen deprivation and other complications for the mother and baby.
NICE recommends that pregnant women with epilepsy should have their antiseizure treatment reviewed by an epilepsy specialist team and should not stop medication without medical supervision.
The goal is therefore not simply to use fewer medicines, but to find the most appropriate treatment at the lowest effective exposure while maintaining seizure control.
What About Lamotrigine and Levetiracetam?
Lamotrigine and levetiracetam are commonly considered among the better-established options for pregnancy safety in some respects. UK safety reviews have found lower risks of major physical birth abnormalities with these medicines than with several older or higher-risk options.
However, the new EURAP analysis still observed a modestly lower birthweight centile with levetiracetam compared with lamotrigine.
This illustrates why one medicine cannot simply be labelled “safe” or “unsafe” for every pregnancy. Dose, seizure type, combination therapy and the mother’s individual circumstances all matter.
What About Valproate and Topiramate?
Both medicines require particular caution in pregnancy.
NICE specifically recommends discussing the risks of sodium valproate and topiramate and following relevant pregnancy-prevention and safety requirements.
Valproate is associated with important risks to fetal development, while topiramate has also been associated with fetal-growth concerns. The new EURAP study adds further evidence that fetal growth should be considered when evaluating antiseizure treatment during pregnancy.
Does the Mother’s Epilepsy Also Matter?
Yes. Medication is only one part of pregnancy risk.
Seizure control, other medicines, nutritional status, maternal health, smoking, diabetes and other pregnancy-related factors can influence fetal growth.
This is why researchers adjusted their statistical models for a wide range of clinical and demographic factors—but observational studies cannot completely eliminate the possibility of residual confounding.
What Should Women Planning Pregnancy Do?
If you have epilepsy and are planning pregnancy:
- Speak with your epilepsy specialist before conception.
- Review the medicine, dose and treatment combination.
- Do not stop medication suddenly.
- Discuss seizure-control goals.
- Review folic-acid supplementation with your healthcare professional.
- Plan appropriate pregnancy monitoring.
- Keep your obstetric and neurology teams informed.
NICE recommends specialist review for women with epilepsy who are pregnant or planning pregnancy.
Can Fetal Growth Be Monitored?
Yes. Pregnancy care can include monitoring fetal growth when clinically appropriate.
The exact schedule depends on the pregnancy, medications, maternal health and other risk factors. Women taking antiseizure medicines should discuss their individual monitoring plan with their obstetric team.
The purpose is not to assume that growth problems will occur, but to identify potential concerns early.
What Does This Mean for India?
For women with epilepsy in India, the same central principle applies: pregnancy medication decisions should be individualized rather than based on internet lists of “safe” or “unsafe” medicines.
A neurologist, obstetrician and other relevant healthcare professionals can consider seizure control, medicine-specific risks, dose and pregnancy history together.
Key Takeaway
The latest EURAP research suggests that poor fetal growth is an important pregnancy outcome to consider when evaluating antiseizure medicines. The risk varied between medicines and was higher with polytherapy than monotherapy.
But the findings should not lead to self-discontinuation of treatment. The safest approach is planned, specialist-led care that balances fetal safety with effective seizure control.
For pregnancy and epilepsy, the goal is not simply fewer medicines—it is the right treatment, at the right dose, with careful monitoring.
Pregnancy and Antiseizure Medicines: FAQs
Can antiseizure medicines cause poor fetal growth?
Some antiseizure medicines have been associated with fetal-growth restriction or lower birthweight. The level of risk varies by medicine and treatment combination.
Is polytherapy riskier than taking one antiseizure medicine?
In the 2026 EURAP study, polytherapy was associated with a higher risk of SGA, severe SGA and low birthweight than monotherapy.
Should I stop my epilepsy medicine if I become pregnant?
No. Do not stop antiseizure medication without medical supervision. NICE recommends specialist review because uncontrolled seizures can also create serious risks.
Which antiseizure medicine is safest during pregnancy?
There is no single medicine that is safest for every person. Choice depends on seizure type, epilepsy syndrome, previous treatment response, dose and pregnancy-specific risks.
Can women with epilepsy have a healthy pregnancy?
Yes. With appropriate preconception planning, seizure management and coordinated obstetric and neurological care, many women with epilepsy have successful pregnancies.
What should I do if I am planning pregnancy?
Arrange a preconception review with your epilepsy specialist and obstetric team before changing any medicine.
