To assess the risk of increased seizure frequency during pregnancy/early postpartum for patients with a catamenial seizure exacerbation pattern (CSEP)

Prior studies demonstrated that seizure frequency is mostly stable during pregnancy/early postpartum when therapeutic drug monitoring is performed. Yet, clinical factors - seizure frequency in the 9 months preconception, epilepsy type, ASM regimen and, in one prior study, CSEP - may influence seizure outcomes.

Clinical data was collected in a longitudinal prospective database of pregnant women with epilepsy at Brigham and Women’s Hospital. Within each participant, baseline seizure frequency was calculated for the 9 months preconception, and it was determined if seizure frequency increased during pregnancy or the postpartum period. CSEP was determined retrospectively by chart review. Associations between categorical variables were evaluated using the Fisher-Exact test.

Ninety-nine patients contributing 114 pregnancies were included from 2013-2018. 24 patients contributing 24 pregnancies were determined to have a CSEP (probable n=17 and possible n=7), 29.2% with generalized and 70.8% with focal epilepsy. Only 50% of CSEP group had been seizure free in the 9 months preconception versus 71.7% in the entire cohort; yet, only 16.7%  were on polytherapy.  The rate of seizure worsening was not significantly different for CSEP group versus the entire cohort during pregnancy (20.8% vs 15.8%) and postpartum (5.3% vs 9.8%). As previously reported, frontal lobe epilepsy was a risk factor: 50.0% of CSEP patients with frontal lobe epilepsy experienced seizure worsening in pregnancy vs 52.9% of all frontal lobe epilepsy patients. 

CSEP patients have a similar risk of seizure worsening in pregnancy/early postpartum to all patients with epilepsy, despite the worse preconception seizure baseline and a lower rate of polytherapy than expected. CSEP does not mediate the high risk of seizure worsening during pregnancy for frontal lobe epilepsy.