(P-165) Trends of Anti-epileptic Drugs Use During Pregnancy in Manitoba, Canada: A 20-year Utilization Study

Background: Both epilepsy and antiepileptic drugs (AEDs) could affect healthy pregnancies and lead to adverse neonatal outcomes. Epilepsy requires continuous treatment during pregnancy to prevent potential trauma associated with seizures.

Objectives: To examine time-trends of utilization of AED therapies among pregnant women in Manitoba, Canada.

Methods: We conducted a population-based cohort study using administrative health databases from the province of Manitoba. Pregnancies of women living in Manitoba between 1995 and 2018 were included. Utilization was identified by Anatomical Therapeutic Chemical codes. Four groups of pregnant women were created based on AED exposure and epilepsy diagnosis. A woman was considered to have epilepsy if she has 1 or more medical claims or 1 or more hospitalization for epilepsy during the 5 years prior to delivery. Utilization trends of AEDs were examined using linear regression.

Results: Out of 273,492 pregnancies identified, 812 (0.3%) had epilepsy diagnosis and were exposed to AEDs, 963 (0.35%) had an epilepsy diagnosis and were unexposed, and 2742 (1%) were exposed to AEDs and did not have epilepsy diagnosis. Overall, the number of pregnancies exposed to AEDs increased from 0.56% in 1997 to 2.21% in 2018 (∆%= 1.66%; CI= -2.21,0.49). The percentage of pregnant women with epilepsy exposed to AEDs was 0.37% in 1997 and 0.36% in 2018 (∆%=-0.01%; CI= -0.11%, 0.2%). The percentage of pregnant woman without epilepsy exposed to AEDs increased from 0.19% in 1997 to 1.85% in 2018 (∆%=1.66%; CI= -0.37, 0.34%).
In the total cohort of pregnancies, 1439 (0.53%) were exposed during the whole pregnancy, 1369 (0.5%) were exposed only in the first trimester, 63(0.02%) were exposed in the second trimester, and 184 (0.07%) were exposed in the third trimester. Clonazepam was the most commonly used AED during the study period (1953 users, 0.71%), followed by gabapentin (785 users, 0.29%) and carbamazepine (449 users, 0.16%).

Conclusions: No major shifts in the use of AEDs were observed among women with epilepsy. Concerns about the increase use of AEDs driven by indications other than epilepsy require additional research on the safety of these agents and their indications to inform prescribers and policymakers.