Topiramate is an effective antiseizure medicine, but pregnancy exposure is associated with important fetal risks and its use is now tightly restricted in women and girls who can become pregnant.
In the UK, topiramate is subject to a formal Pregnancy Prevention Programme. The rules apply whether topiramate is being used for epilepsy or migraine, although the advice after pregnancy is suspected differs because abruptly stopping an antiseizure medicine can itself be dangerous.
What is topiramate used for?
Topiramate is used to treat several seizure types and epilepsy syndromes, either alone or in combination with other medicines. It is also used for migraine prevention.
For some people with epilepsy it provides useful seizure control after other treatments have failed or caused unacceptable side effects. This is why reproductive restrictions do not mean the medicine has no legitimate role.
Why the UK rules changed
The MHRA strengthened topiramate restrictions after reviewing accumulating evidence of harm following exposure during pregnancy.
The review confirmed increased risks of congenital malformations and impaired fetal growth and identified a possible increased risk of neurodevelopmental disorders including intellectual disability, autism spectrum disorder and attention deficit hyperactivity disorder.
Current UK Pregnancy Prevention Programme
Topiramate must not be used in women and girls of childbearing potential unless the conditions of the Pregnancy Prevention Programme are fulfilled.
The programme requires:
- assessment of the potential for pregnancy
- a pregnancy test to exclude pregnancy before treatment begins
- clear counselling about pregnancy-related risks
- highly effective contraception throughout treatment
- continued highly effective contraception for at least four weeks after the final dose
- completion of a Risk Awareness Form when treatment begins
- completion of the Risk Awareness Form again at annual treatment reviews
- provision of the official patient information materials
The programme can apply even when someone is not currently sexually active
MHRA guidance states that the Pregnancy Prevention Programme also applies to women and girls of childbearing potential who are not sexually active unless the prescriber considers there are compelling reasons why there is no risk of pregnancy.
The purpose is to prevent gaps in protection if circumstances change between medical reviews.
How large is the congenital-malformation risk?
MHRA data indicate that major congenital malformations occur in approximately 4 to 9 babies in every 100 exposed to topiramate during pregnancy.
For comparison, the background rate in the general population is approximately 1 to 3 in every 100.
The types of malformation reported include oral clefts and other structural abnormalities.
The congenital-malformation risk appears dose related
Available evidence suggests that higher doses are associated with higher risk.
However, regulators have not identified a threshold dose below which there is no reproductive risk. A lower dose should therefore not be described as completely safe in pregnancy.
Fetal growth is another established concern
Topiramate exposure is associated with increased rates of babies being born small for gestational age and with lower birth weight.
The MHRA review reported small-for-gestational-age outcomes in approximately 18 in every 100 topiramate-exposed pregnancies.
For comparison, around 5 in every 100 babies born to women with epilepsy who were not taking an antiseizure medicine were small for gestational age in the cited evidence.
Potential neurodevelopmental risk
Observational studies have raised concern that prenatal topiramate exposure may also be associated with later neurodevelopmental disorders.
The MHRA review reported a possible approximately two- to three-fold increased risk of intellectual disability, autism spectrum disorder and attention deficit hyperactivity disorder compared with children born to mothers with epilepsy who were not taking antiseizure medication.
This evidence is important but should be described carefully. These are observational data, which can be affected by differences in epilepsy severity, dose, other medicines and other clinical factors. The association is serious enough to have changed regulatory practice, but it does not mean every exposed child will develop a neurodevelopmental disorder.
Topiramate in pregnancy for epilepsy
In the UK, topiramate should not be used for epilepsy during pregnancy unless there is no suitable alternative treatment.
This recognises two competing risks: the reproductive risks of topiramate and the dangers of inadequately controlled epilepsy.
If topiramate is the only medicine that controls a person’s seizures, abruptly withdrawing it may create a substantial immediate risk.
Topiramate in pregnancy for migraine is different
Topiramate is contraindicated for migraine prevention during pregnancy.
Unlike epilepsy, migraine prophylaxis does not usually create a risk of dangerous recurrent seizures if topiramate is withdrawn.
This difference explains why MHRA advice after a suspected pregnancy is different for migraine and epilepsy.
If pregnancy is suspected while taking topiramate for epilepsy
Do not stop topiramate suddenly without medical advice.
The MHRA advises people taking topiramate for epilepsy who think they may be pregnant to arrange an urgent appointment with their GP or epilepsy team within a few days.
Stopping suddenly can cause seizures to return, become more frequent or last longer.
If pregnancy is suspected while taking topiramate for migraine
The MHRA advises people using topiramate for migraine prevention who think they may be pregnant to stop topiramate and contact their GP.
This distinction should not be overlooked when general pregnancy warnings about topiramate are discussed.
Planning a pregnancy while taking topiramate
Anyone taking topiramate for epilepsy who wants to become pregnant should arrange specialist review before stopping contraception.
The epilepsy team can consider whether another effective antiseizure medicine is available and whether a gradual transition can be completed before conception.
The aim is to establish seizure control on the safest effective regimen before pregnancy begins rather than making rushed treatment changes after conception.
Contraception must continue during treatment and afterwards
Highly effective contraception should be used throughout topiramate treatment and for at least four weeks after the final dose.
This period allows topiramate to clear after treatment ends and forms part of the formal UK Pregnancy Prevention Programme.
Topiramate can interact with hormonal contraception
This is particularly important because the medicine for which pregnancy prevention is required can itself reduce the effectiveness of some hormonal contraceptives.
Topiramate has enzyme-inducing activity that depends partly on dose and can reduce exposure to steroid contraceptive hormones.
The safest contraceptive method should therefore be selected with the prescriber, pharmacist or specialist contraception service rather than assuming a standard oral contraceptive will remain sufficiently reliable.
The dedicated Antiseizure Medicines and Contraception page explains these interactions in more detail.
Which contraceptive methods avoid enzyme-induction problems?
Methods such as copper intrauterine devices and levonorgestrel intrauterine systems are not made less effective by hepatic enzyme induction.
Depot medroxyprogesterone acetate is also generally considered unaffected by enzyme-inducing antiseizure medicines.
The individual method still needs to satisfy the Pregnancy Prevention Programme and suit the person’s wider health and preferences.
Emergency contraception needs special consideration
Enzyme-inducing antiseizure medicines can reduce the effectiveness of oral emergency contraception.
A copper intrauterine device is not affected by enzyme induction and is the most effective method of emergency contraception where appropriate.
Anyone taking topiramate who needs emergency contraception should tell the pharmacist, GP or sexual-health service about the medicine so the interaction can be taken into account.
Annual review is part of the programme
The MHRA recommends review of topiramate treatment at least once each year.
The review should confirm whether topiramate is still needed, whether contraception remains appropriate, whether reproductive plans have changed and whether the person understands the pregnancy risks.
The Risk Awareness Form is completed again at annual review.
The warning is relevant to girls approaching puberty
NICE recommends discussing reproductive safety before a girl reaches the point at which pregnancy could occur if she is likely to remain on antiseizure treatment.
This is not an assumption about sexual activity. It is an attempt to prevent someone reaching reproductive age on a medicine with important pregnancy risk without having been informed and reviewed.
Folic acid is important but does not remove the topiramate risk
People planning pregnancy are advised to take folic acid according to current national guidance.
However, folic acid should not be presented as a way to make topiramate safe during pregnancy. It does not remove the known risks of congenital malformation, fetal growth restriction or the possible neurodevelopmental risk.
See Preconception Planning, Folic Acid and Epilepsy for the wider pre-pregnancy plan.
Changing antiseizure medicine is not risk-free
If topiramate is controlling seizures well, changing treatment can cause breakthrough seizures or expose the person to side effects from a replacement medicine.
Medication transitions should therefore be gradual and specialist led.
A pregnancy-prevention rule does not mean the safest response is automatically to stop the medicine. It means reproductive risk must be actively managed while treatment options are reviewed.
The replacement medicine matters
Lamotrigine and levetiracetam are among the better-studied antiseizure medicines in pregnancy and have lower rates of major congenital malformations than several alternatives in current safety reviews.
However, they are not interchangeable with topiramate for every epilepsy syndrome or seizure type.
Treatment selection must still be based on the person’s epilepsy as well as reproductive safety.
Topiramate and body weight
Topiramate can reduce appetite and cause weight loss in some people.
That does not explain the whole fetal-growth signal seen in pregnancy studies, but maternal weight, nutrition and fetal growth all deserve attention when pregnancy occurs despite treatment or when topiramate has to be continued because no suitable alternative exists.
Pregnancy monitoring if topiramate must continue
If topiramate is continued during pregnancy for epilepsy because no suitable alternative treatment exists, care should be coordinated between the epilepsy team and specialist maternity services.
The clinical plan may include detailed fetal assessment, growth surveillance and close review of seizure control and medicine dosing.
Prenatal imaging can identify some structural abnormalities but cannot predict all later developmental outcomes.
Breastfeeding is a separate question from pregnancy exposure
The reproductive risks described above relate to exposure during pregnancy and should not simply be copied across to breastfeeding.
Topiramate can enter breast milk and infant exposure can be measurable. Most reported breastfed infants have remained well, but diarrhoea and sedation have been described.
The dedicated Breastfeeding and Antiseizure Medicines page covers lactation separately.
Topiramate is not valproate
Topiramate and valproate both require Pregnancy Prevention Programmes in women and girls who can become pregnant, but their evidence bases and regulatory rules are not identical.
Valproate has a particularly extensive body of evidence showing congenital and neurodevelopmental harm and has additional UK prescribing restrictions affecting new treatment in people under 55.
Topiramate has its own distinct pregnancy-risk profile and its own programme. The two medicines should not be treated as interchangeable examples of the same risk.
See Valproate and Reproductive Safety for the separate valproate rules.
What the Risk Awareness Form is for
The Risk Awareness Form is designed to confirm that reproductive risks and the Pregnancy Prevention Programme have been discussed.
It is signed by the healthcare professional and the patient, or responsible person where appropriate, when treatment begins and again at annual reviews.
The patient should receive a copy and a copy is kept in the medical record.
What pharmacists are asked to do
Topiramate packs carry pregnancy-warning information. Pharmacists are expected to provide the patient card to female patients and to ask women and girls of childbearing potential whether they are using highly effective contraception.
If appropriate contraception is not in place, the person should be directed back to the GP or specialist for review.
Questions worth asking at a topiramate review
- Why is topiramate being used for my epilepsy?
- Have suitable alternative medicines been considered?
- What would happen to my seizure control if treatment changed?
- Does the Pregnancy Prevention Programme apply to me?
- Is my contraceptive method highly effective and unaffected by topiramate?
- When was my last Risk Awareness Form completed?
- What should I do if I think I am pregnant?
- What should I do before trying for pregnancy?
- If topiramate has to continue during pregnancy, what extra monitoring would be needed?
- What is the plan for breastfeeding after birth?
The central message
Topiramate has a real place in epilepsy treatment, but exposure during pregnancy is associated with increased risk of major congenital malformations and impaired fetal growth, with additional concern about neurodevelopmental outcomes.
For women and girls who can become pregnant in the UK, topiramate is therefore subject to a Pregnancy Prevention Programme requiring pregnancy exclusion before starting, highly effective contraception during treatment and for at least four weeks afterwards, risk counselling, annual review and signed documentation.
If pregnancy occurs while topiramate is being used for epilepsy, the medicine should not be stopped abruptly. Urgent specialist review is the appropriate response because both fetal exposure and uncontrolled seizures need to be considered.
Related pages: Hormones, Contraception & Pregnancy · Preconception Planning, Folic Acid and Epilepsy · Antiseizure Medicines and Contraception · Valproate and Reproductive Safety · Breastfeeding and Antiseizure Medicines · Treatment Options
Sources and further reading
MHRA — Topiramate: introduction of new safety measures and Pregnancy Prevention Programme
MHRA — Topiramate: review of safety in pregnancy
NICE NG217 — Principles of treatment, safety, monitoring and withdrawal
NICE NG217 — Treating epileptic seizures
MHRA — Antiepileptic drugs in pregnancy: comprehensive safety review
Evidence checked: September 2026.