Women with epilepsy often need medication to prevent seizures during pregnancy. Previous studies have found an association between exposure to the antiseizure medication valproate during pregnancy and risk of autism and low IQ in the offspring.
The current study which is the largest to date includes more than 4 million pregnancies and not only confirms this risk, but also shows that pregnancy use of the drug topiramate is connected to similar risks of autism and intellectual disability in the child. Valproate and topiramate are frequently used for epilepsy and migraine, and valproate is also used for bipolar disorder.
The safety committee of the European and British Medicines Agency (Pharmacovigilance Risk Assessment Committee (PRAC) under the European Medicines Agency (EMA) and the Medicines and Healthcare products regulatory agency (MHRA) in the UK) have started safety assessments of topiramate as a result of the study.
The Nordic register-based study of antiepileptic drugs in Pregnancy (SCAN AED) funded by NordForsk is a large and unique study collecting data on the use of antiseizure medication among pregnant women across the Nordic countries. Researchers from Denmark, Finland, Iceland, Norway, and Sweden collected registry data on more than 4 million Nordic children born between 1996 and 2017; of these, 31,047 children were born to mothers who had redeemed prescriptions for antiseizure medication during pregnancy. The researchers studied if the offspring had been diagnosed with autism or other neurodevelopmental disorders.
The results show that exposure to the drugs topiramate and valproate was associated with a two- to four-fold increased risk of autism and intellectual disability. The study further confirms previous results that the most used antiseizure drug in pregnancy (lamotrigine) is not associated with risk of autism and intellectual disability in the offspring. Neither levetiracetam, another much used drug in people with epilepsy were associated with increased risk of these disorders.
“We found that children of women with epilepsy exposed to topiramate or valproate during pregnancy had a two-to-four-fold increased risk of autism and intellectual disability compared to children not exposed to any antiseizure medications,” says lead investigator of SCAN AED Marte-Helene Bjørk. “Epilepsy, migraine, and bipolar disorder are common disorders in women of childbearing age. It is important that women having these disorders are offered information on which treatment is safest in pregnancy so that they together with their doctor can take informed decisions on the best treatment.”