Published: 9 April 2025
Safety Information
Alert communication
Use of carbamazepine during pregnancy: Growth risks for babies
9 April 2025
A recent observational study found that carbamazepine use during pregnancy may increase the risk of the baby being born small for gestational age or with microcephaly (baby’s head is smaller than expected).1
The Tegretol (carbamazepine) data sheet has been updated to include information on these risks.
Advice for consumers and caregivers
Information for healthcare professionals
Products affected
Further information
Useful links
Advice for consumers and caregivers
- Do not stop taking carbamazepine without talking to your doctor.
- Carbamazepine could harm the way an unborn baby grows and develops during pregnancy.
- Babies born to people who took carbamazepine during pregnancy were found to have increased risks of having a smaller head than expected and being smaller than expected.
- Anyone who could get pregnant should use effective contraception while taking carbamazepine and for two weeks after the last dose.
- Speak with your doctor if you are pregnant or planning to become pregnant while taking carbamazepine.
Information for healthcare professionals
- Congenital malformations and neurodevelopmental disorders have been reported in children following prenatal carbamazepine exposure.
- Carbamazepine should be used during pregnancy only if the potential benefit justifies the potential risks to the fetus.
- Refer people taking carbamazepine who become pregnant for specialist advice.
- People who are planning a pregnancy should be switched to an appropriate alternative treatment prior to conception and before contraception is stopped.
- More recently, an observational study found that prenatal carbamazepine exposure was associated with increased risks of being born small for gestational age or with microcephaly in both the overall population and in children born to people with epilepsy.
- For people of childbearing potential, consider performing pregnancy tests before starting carbamazepine and ensure that they are using effective contraception (eg, intrauterine device, medroxyprogesterone injection) during treatment and for two weeks after the last dose.
- Inform people of childbearing potential about the risks of fetal harm if they become pregnant.
- The Tegretol data sheet contains new safety information about the risks of carbamazepine use in pregnancy.
Products affected
Carbamazepine is a medicine used to treat epilepsy and other conditions such as bipolar affective disorders, alcohol-withdrawal syndrome, trigeminal neuralgia and diabetic neuropathy.
| Product name | Sponsor |
|---|---|
| Tegretol tablet | Novartis |
| Tegretol CR modified release tablet | Novartis |
| Tegretol Syrup | Novartis |
Further information
The Tegretol data sheet already included information about the risk of congenital malformations and neurodevelopmental disorders. The risks of microcephaly and small for gestational age were recently noted in an observational study using registry data from Denmark, Finland, Iceland, Norway and Sweden.1
- In the overall study population, there were over 4.4 million children including 27,070 prenatally exposed to an antiepileptic medicine of whom 3,424 were exposed to carbamazepine alone.
- In children of women with epilepsy, there were over 38,000 children including 16,487 prenatally exposed to an epileptic medicine of whom 2,669 were exposed to carbamazepine alone.
The authors reported that in the overall study population, prenatal monotherapy exposure to carbamazepine was associated with increased risks of being born small for gestational age (adjusted odds ratio [aOR]: 1.25, 95% confidence interval [CI]: 1.12–1.40) or with microcephaly (aOR: 1.43, 95% CI: 1.17–1.75). The elevated risks remained when restricting the analysis to children of mothers with epilepsy (small for gestational age: aOR: 1.27, 95% CI: 1.11–1.47; microcephaly: aOR: 1.51, 95% CI: 1.17–1.95).1
Small for gestational age is a term used to describe a baby who is smaller than expected for their gestational age (number of weeks of pregnancy). In New Zealand, it is defined as an estimated fetal weight or birth weight below the 10th customised percentile.2
Microcephaly is defined as an occipito-frontal circumference of greater than 2 standard deviations below the mean for age, sex and ethnicity, which is equivalent to a measurement less than the 3rd percentile.3
Babies born small for gestational age or with microcephaly may have short- and long-term health problems.1
New Zealand pharmaceutical dispensing data indicates that the use of carbamazepine during pregnancy has gradually decreased over the last 10 years, from more than 80 pregnant people dispensed carbamazepine during 2014 to fewer than 50 during 2023.4
Useful links
- Search for consumer medicine information (CMI) and data sheets
- Epilepsy medicines and pregnancy consumer information leaflet
- Report an adverse event to a medicine (side effect)
References
- Christensen J, Zoega H, Leinonen MK, et al. 2024. Prenatal exposure to antiseizure medications and fetal growth: a population-based cohort study from the Nordic countries. The Lancet Regional Health Europe 38: 100849. DOI: 10.1016/j.lanepe.2024.100849 (accessed 23 January 2025).
- Te Whatu Ora – Health New Zealand. 2023. Small for gestational age and fetal growth restriction in Aotearoa New Zealand He Aratohu Ritenga Haumanu mō te Tōhuatanga Kōpiri me te Pakupaku Rawa. A clinical practice guideline: Summary of recommendations. URL: tewhatuora.govt.nz/assets/Publications/Obstetrics/Small-for-Gestational-Age-and-Fetal-Growth-Restriction-in-NZ-Clinical-Practice-Guideline-Summary-of-recommendations.pdf (accessed 23 January 2025).
- Paediatric Neurology Clinical Network. 2021 Microcephaly Diagnostic Guidelines 22 February 2021. URL: org.nz/guidelines/microcephaly-diagnostic-guidelines/ (accessed 23 January 2025).
- Te Whatu Ora – Health New Zealand. National Collections Data.
