Topiramate is known to increase the risk of oral clefts when taken by pregnant women with epilepsy. However, it is unknown if lower doses — such as those for bipolar disorder — confer the same risk.
Researchers studied data on 1,360,101 mother-infant pairs, including 2,425 pairs exposed to topiramate during the first trimester.
They found that the risk of oral clefts was 4.1 per 1,000 live births in the topiramate group compared with 1.1 per 1,000 live births in the unexposed group (relative risk 2.90).
Restricting the study to women with epilepsy, they found that the risk of oral clefts was 12.3 per 1,000 infants born to mothers who took topiramate (relative risk 8.30). By contrast, in women taking topiramate for other indications, such as bipolar disorder, the risk of oral clefts was 2.1 per 1,000 exposed infants (relative risk 1.45).
Reporting in Neurology (online, 27 December 2017), the researchers said the findings indicated that larger doses of topiramate taken for epilepsy may confer a higher risk of oral clefts[1]
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References
[1] Hernandez-Diaz S, Huybrechts KF, Desai RJ et al. Topiramate use early in pregnancy and the risk of oral clefts. Neurology 2018. doi: 10.1212/WNL.0000000000004857