416-813-6780 (Toronto and GTA)
Motherisk Nausea and Vomiting of Pregnancy Helpline
Alcohol and Substance
Pregnancy & Breastfeeding Resources
Read more in our News Archive
Is carbamazepine safe to take during pregnancy?
Jeremy Matlow and and Gideon Koren, MD, FRCPC, FACMT
Some of my pregnant patients are afraid to take their antiepileptic drugs during pregnancy because of the known risk of malformations and the neurodevelopmental problems associated with valproic acid. Are there similar concerns with carbamazepine?
Similar to valproic acid, carbamazepine increases the risk of neural tube defects; however, it does not increase the risk of other malformations. Carbamazepine is also not associated with an increased risk of developmental delay.
Certaines de mes patientes enceintes ont peur de prendre leurs médicaments contre l'épilepsie durant la grossesse en raison des risques connus de malformations et de problèmes neurodéveloppementaux associés à l'acide valproïque. Y a-t-il des inquiétudes semblables avec la carbamazépine?
À l'instar de l'acide valproïque, la carbamazépine augmente le risque d'anomalies du tube neural; par ailleurs, elle n'augmente pas le risque de malformations et n'est pas associée à un risque accru de retard du développement.
For the past few decades, carbamazepine (CBZ) has been used as an effective treatment of seizures, bipolar disorder, and certain types of pain. Carbamazepine has been viewed by many as the antiepileptic drug (AED) of choice during pregnancy,1 as there are more studies on the fetal outcomes associated with in utero CBZ monotherapy compared with other AEDs.2 Treatment of active epilepsy is important during pregnancy because seizures can lead to falls, injury, and physical stress that can endanger the health of the woman and the fetus.3 Carbamazepine has not been associated with increased risk of pregnancy complications such as cesarean section, preeclampsia, or premature delivery,4 and its contributions to congenital malformations and neurodevelopmental anomalies have become clearer owing to recent large studies.
A 2008 review concluded that CBZ monotherapy has one of the lowest risks of teratogenicity among antiepileptic treatments.2 The review summarized 9 studies that included women taking CBZ monotherapy as the exposed group. Six studies used epilepsy controls (n = 1613 for children born to epilepsy controls, n = 2533 for children exposed to CBZ monotherapy) and 3 used healthy controls (n = 2308 for children born to healthy controls, n = 542 for children exposed to CBZ monotherapy). Only 1 of the 9 studies had a relative risk ratio significantly greater than 1.0 for malformations when taking CBZ monotherapy compared with controls, and that was in one of the studies using healthy controls.5
Exposure to CBZ during pregnancy has been associated with an increased risk of neural tube defects (NTDs) (0.2% to 1% vs 0.1% in the general population),6-8 and its association with other major malformations has been clarified in a recent systematic review of 8 studies.9 The overall risk of all major congenital malformations was 3.3% with first-trimester CBZ monotherapy exposure (89 of 2680 exposed pregnancies, 95% CI 2.7% to 4.2%). The authors also conducted a case-controlled study using the EUROCAT database of 3 881 592 births and 98 075 major congenital malformations in Europe from 1995 to 2005. Within the database, spina bifida was significantly associated with exposure to CBZ monotherapy compared with no AED exposure (odds ratio [OR] 2.6, 95% CI 1.2 to 5.3), but the risk was significantly lower when CBZ was compared with valproic acid exposure (OR 0.2, 95% CI 0.1 to 0.6). Compared with no AED exposure, there was no significant association between exposure to CBZ monotherapy and total anomalous pulmonary venous return, cleft lip with or without cleft palate, diaphragmatic hernia, or hypospadias. Additionally, compared with other AED monotherapies (excluding valproic acid), there was no significant association between CBZ exposure and either spina bifida or hypospadias, and the risk was actually lower for cleft lip with or without cleft palate (OR 0.1, 95% CI 0.0 to 0.6).
Several early studies suggested increased neurodevelopmental anomalies in children exposed to AEDs in utero.10,11 A 2010 meta-analysis of 7 studies analyzed full-scale, performance, and verbal IQ scores in 151 CBZ-exposed children, 58 unexposed children born to mothers with epilepsy, and 436 unexposed children born to mothers without epilepsy.12 In 2 of the studies that used the Bayley or McCarthy IQ scales, which measure full-scale IQ only, there was no significant difference between the CBZ-exposed children and the unexposed children. In 3 other studies, when using the Wechsler IQ scale, there was a significant difference between the CBZ-exposed children and the children in the unexposed control group in performance IQ only; however, this significance disappeared when compared with the children in the epilepsy control group (P < .002). More current studies have confirmed that CBZ exposure does not significantly decrease average reported IQ,13 fluency and originality,14 and core language scores.15
There is a 2- to 10-fold increased risk of NTDs in women with epilepsy taking CBZ; however, the risks associated with CBZ are not as great as those associated with valproic acid. It is therefore important to discuss epilepsy treatments with women of childbearing age in the planning phase, so that they can begin early supplementation with 5 mg of folic acid and discontinue using valproic acid before pregnancy. Additionally, it is important to screen with a combination of a level 2 ultrasound and either maternal blood or amniotic a-fetoprotein testing at 16 to 18 weeks of gestation to rule out NTDs. Unlike valproic acid, CBZ does not appear to have adverse effects on neurobehavioural development.
Motherisk questions are prepared by the Motherisk Team at The Hospital for Sick Children in Toronto, Ont. Mr. Matlow is a graduate student in the Department of Pharmacology at the University of Toronto. He is supported by an Ontario Graduate Scholarship. Dr. Koren is Director of the Motherisk Program. Dr. Koren is supported by the Research Leadership for Better Pharmacotherapy during Pregnancy and Lactation. He holds the Ivey Chair in Molecular Toxicology in the Department of Medicine at the University of Western Ontario in London.
Do you have questions about the effects of drugs, chemicals, radiation, or infections in women who are pregnant or breastfeeding? We invite you to submit them to the Motherisk Program by fax at 416 813-7562; they will be addressed in future Motherisk Updates.
Copyright © the College of Family Physicians of Canada
Can Fam Physician
Vol. 58, No. 2, February 2012, 163-164
Copyright © 2012 by The College of Family Physicians of Canada
- Delgado-Escueta AV, Janz D. Consensus guidelines: preconception counseling, management, and care of the pregnant woman with epilepsy. Neurology 1992;42(4 Suppl 5):149-60. Abstract/FREE Full Text
- Eadie MJ. Antiepileptic drugs as human teratogens. Expert Opin Drug Saf 2008;7(2):195-209. CrossRef | Medline
- Szabo CA. Patient page. Risk of fetal death and malformation related to seizure medications. Neurology 2006;67(3):E6-7. FREE Full Text
- Harden CL, Sethi NK.Epileptic disorders in pregnancy: an overview. Curr Opin Obstet Gynecol 2008;20(6):557-62. CrossRef | Medline
- Samrén EB, van Dujin CM, Christiaens GC, Hofman A, Lindhout D. Antiepileptic drug regimens and major congenital abnormalities in the off-spring. Ann Neurol 1999;46(5):739-46. CrossRef | Medline
- Rosa FW. Spina bifida in infants of women treated with carbamazepine during pregnancy. N Engl J Med 1991;324(10):674-7. Medline
- Kaaja E, Kaaja R, Hiilesmaa V. Major malformations in offspring of women with epilepsy. Neurology 2003;60(4):575-9. Abstract/FREE Full Text
- Morrow J, Russell A, Guthrie E, Parsons L, Robertson I, Waddell R, et al. Malformation risks of antiepileptic drugs in pregnancy: a prospective study from the UK Epilepsy and Pregnancy Register. J Neurol Neurosurg Psychiatry 2006;77(2):193-8. Epub 2005 Sep 12. Abstract/FREE Full Text
- Jentink J, Dolk H, Loane MA, Morris JK, Wellesley D, Garne E, et al. Intrauterine exposure to carbamazepine and specific congenital malformations: systematic review and case-control study. BMJ 2010;341:c6581. Abstract/FREE Full Text
- Hill RM, Verniaud WM, Rettig GM, Tennyson L, Craig JP. Relation between antiepileptic drug exposure of the infant and developmental potential. In: Janz D, Dam M, Richens A, Bossi L, Helge H, Schmidt DA, editors. Epilepsy, pregnancy, and the child. New York, NY: Raven Press; 1982. p. 409-17.
- Speidel BD, Medaow SR. Maternal epilepsy and abnormalities of the fetus and newborn. Lancet 1972;2(7782):839-43. Medline
- Banach R, Boskovic R, Einarson T, Koren G. Long-term developmental outcome of children of women with epilepsy, unexposed or exposed prenatally to antiepileptic drugs: a meta-analysis of cohort studies. Drug Saf 2010;33(1):73-9. Medline
- Meador KJ, Baker GA, Browning N, Clayton-Smith J, Combs-Cantrell DT, Cohen M, et al. Cognitive function at 3 years of age after fetal exposure to antiepileptic drugs. N Engl J Med 2009;360(16):1597-605. CrossRef | Medline
- McVearry KM, Gaillard WD, VanMeter J, Meador KJ. A prospective study of cognitive fluency and originality in children exposed in utero to carbamazepine, lamotrigine, or valproate monotherapy. Epilepsy Behav 2009;16(4):609-16. Epub 2009 Nov 4. CrossRef | Medline
- Nadebaum C, Anderson VA, Vajda F, Reutens DC, Barton S, Wood AG. Language skills of school-aged children prenatally exposed to antiepileptic drugs. Neurology 2011;76(8):719-26. Abstract/FREE Full Text