Abstracts

Rationale: When women with epilepsy become pregnant, continuous treatment with antiepileptic drugs (AEDs) is often needed. During the past decades, we have learned much about the teratogenic effects of AEDs, and many new AEDs have been introduced to the market. In the present study, we aimed to examine trends in the use of AEDs during pregnancy using national data across two decades in Denmark. Methods: We included 1,257,710 pregnancies leading to live birth in Denmark between 1st January 1997 and 31st December 2016. Information on redeemed prescriptions for AEDs was obtained from the Danish National Prescription Register. We examined the trends of the most frequently used AEDs in Denmark, including Phenobarbital, Clonazepam, Carbamazepine, Oxcarbazepine, Valproate, Lamotrigine, Topiramate, Gabapentin, Levetriacetam, Zonisamide, Pregabalin and Clobazam. Results: Use of AEDs was identified in 6,450 pregnancies, corresponding to 5.1 per 1,000 pregnancies resulting in live births. The proportion of pregnant women in treatment with AEDs increased over time, from <3.5 per 1,000 pregnancies in 1997 to 6.9 per 1,000 pregnancies in 2016. The three most commonly used AEDs in 2016 were Lamotrigine, Levetiracetam, and Pregabalin. Lamotrigine accounted for the majority of the increase in the overall trend. In contrast, the use of valproate during pregnancy decreased over time, and in 2016, only 0.2 per every 1,000 pregnant women were using valproate. Conclusions: The overall use of AEDs has increased in pregnant women from 1997 to 2016. The use of Valproate in Danish pregnant women has decreased in recent years following reports of adverse birth outcomes after Valproate exposure in pregnancy. Lamotrigine is now the main AED used in pregnant women in Denmark. Funding: Novo Nordisk Foundation, Danish Epilepsy Association, Central Denmark Region.