Use of antiepileptic drugs by trimester.

Objective: To determine which antiepileptic drugs pregnant women receive by trimester.

Methods: This retrospective cohort study using the IBM Watson Health MarketScan Research Databases evaluated which antiepileptic drugs pregnant women with epilepsy received by trimester. Women with aged 15-54 years with a history of seizure disorder who underwent a delivery hospitalization between 2008 and 2017 were included in the analysis. Descriptive statistics were performed.

Results: Of 34,144 women with a seizure disorder diagnosis and a delivery hospitalization, 10,289 (30.1%) received an anti-epileptic medication during pregnancy of which more than half received lamotrigine or levetiracetam. Other antiepileptic medications used by >5% of the population during any one trimester in the study period included carbamazepine, clonazepam, and topiramate. In evaluating medication use in the 1st trimester versus the 2nd trimester, clonazepam use decreased 32.0% (95% CI 60.0%, 77.0%) from 5.6% to 3.8% of patients receiving antiepileptics from the 1st to the 2nd trimester, gabapentin deceased 22.1% (95% CI 0.68%, 0.90%) from 4.1% to 3.2%, and topiramate decreased 30.0% (95% CI 62.8%, 77.9%) from 7.2% to 5.1%. In comparison, levetiracetam increased from 22.5% to 33.3% between the 1st and 3rd trimester and lamotrigine 22.2% to 27.5% between the 1st and 3rd trimester, 48.3% and 24.0% increases respectively.

Conclusion: Antiepileptic drugs with less favorable fetal risk profiles such as topiramate decreased by trimester while medications with more favorable fetal risk profiles such as lamotrigine and levetiracetam increased. These findings broadly support that there are opportunities to improve pre-conceptional counseling of women with epilepsy.