Trends in Use of Antiseizure Medicines in Women With Epilepsy in Pregnancy During 2018-2023 in an Irish Maternity Hospital: A Cohort Study.

OBJECTIVE: This study aimed to describe and explore the trends of antiseizure medicine (ASM) use in women with epilepsy (WWE) in pregnancy over a 6-year period. METHODS: This observational cohort study used routinely collected electronic health record (EHR) data from a large maternity hospital in Dublin, Ireland, with > 9000 births annually. WWE attending during pregnancy between 2018 and 2023 were included. Descriptive statistics and linear and negative binomial regression models were used to assess temporal trends. Outcomes included individual ASM exposure, ASM safety category ('Known safest', 'Uncertain risk' and 'Higher risk') and temporal trends in ASM use. RESULTS: There were 286 ASM-exposed pregnancies in WWE. The overall proportion of ASM-exposed pregnancies in WWE ranged between 87.7% and 95.7% per year. Trends for most ASMs and overall safety categories did not change significantly or had insufficient data to assess trends over time. Levetiracetam (60.1%) and lamotrigine (31.5%) were most frequently used overall. Zonisamide use decreased significantly (-0.395, p = 0.029), although this finding should be interpreted cautiously given the small number of exposures (n = 13). ASM polytherapy occurred in 24.8% of pregnancies. Some newer ASMs were introduced during the study, and a decline in use of some higher-risk ASMs was observed, although findings were not significant. CONCLUSIONS: In this single-centre EHR cohort, trends in use of ASMs in WWE appeared relatively stable, although analyses of less commonly used ASMs were limited by very small numbers. ASMs with safer pregnancy profile were most frequently used in WWE in pregnancy. Additional data are needed to further assess trends and outcomes and to determine the place of newer generation ASMs in WWE in pregnancy.