Neurological care and outcomes in a cohort of Canadian pregnant patients with epilepsy

Purpose: To characterize anti-seizure medication (ASM) use over time, therapeutic drug monitoring, ASM dose adjustments and gestational seizure frequency among Canadian people with epilepsy of childbearing potential seen in an urban tertiary care center.

Methods: Participants were retrospectively identified from the medical records of pregnant patients with epilepsy seen at the University Health Network Comprehensive Epilepsy Program between 2014 and 2021. A descriptive analysis of outcomes, a logistic regression analysis of the odds of patients being on three ASMs associated with higher rates of teratogenicity (i.e., valproate, carbamazepine, and topiramate) over time, and a second logistic regression for predictors of seizure freedom during pregnancy were performed.

Results: 195 pregnancies were included: 52 % had a maternal diagnosis of generalized epilepsy and 92 % were prescribed at least one ASM, with 75 % on monotherapy. The majority underwent therapeutic drug monitoring (77 %) with approximately two-thirds requiring dose adjustments (69 %), typically dosage increases (82 %). The proportion of patients on either valproate, topiramate, or carbamazepine decreased over time (OR=0.80; p<0.01). Fifty-seven percent of pregnancies maintained seizure freedom, with seizure-freedom for ≥1 year prior to conception being the strongest predictor of this outcome (OR of gestational seizure recurrence=0.04; p < 0.01).

Conclusion: The proportion of patients on three ASMs associated with higher rates of teratogenicity has decreased over the duration of this study. Seizure-freedom prior to conception was associated with a decreased risk of gestational seizure recurrence.