Trends in the prescription of anti-seizure medicines for pregnant women outpatients with epilepsy during 2016–2020 in Japan

Purpose: The temporal trends in prescribing anti-seizure medicines (ASMs) for pregnant women with epilepsy are unclear. In this study, we investigated the trends in ASM prescriptions in pregnant Japanese women with epilepsy. Methods: Administrative data (as of December 2021), pertaining to Japanese pregnant outpatient women with epilepsy, aged 16–49 years, who visited hospitals between January 1, 2016 and December 31, 2020 were included in the study. Annual prescription trends in ASMs during this period were calculated based on the proportions. The Cochran–Armitage trend test was used to evaluate the proportion of prescriptions for each ASM. Results: The numbers of pregnant women with epilepsy were 404, 421, 368, 378, 386 for the years 2016, 2017, 2018, 2019, and 2020, respectively. As of 2020, levetiracetam had the highest proportion of prescriptions, followed by lamotrigine and valproic acid. From 2016 to 2020, the proportions of levetiracetam and lamotrigine prescribed for pregnant women with epilepsy have increased significantly from 19.1% to 30.8% and from 12.1% to 18.4%, respectively. In contrast, there was no temporal change in the proportion of valproic acid prescribed, which was 12.4% in 2016 and 10.1% in 2020. Conclusion: Our findings suggest that the trends in the prescription of ASMs in Japanese pregnant women outpatients with epilepsy have shifted toward ASMs with a lower teratogenic risk.