Trends in the use of anti-epileptic drugs during pregnancy in the netherlands

Background: The use of anti-epileptic drugs (AEDs) during pregnancy is associated with an increased risk of birth defects. Since epilepsy itself is also associated with potential risks for mother and child, an optimal AED treatment is needed. Over the past years, the introduction of new AEDs and the amendments of guidelines have changed the use of AEDs in this vulnerable group of patients. The extend of the changes over time in the Netherlands has not been studied before. Objectives: To compare the use of different AEDs in pregnant women over the past 10 years in the Netherlands. Methods: This retrospective cohort study data is based on data from the register that is being used to submit Dutch cases to the EURAP study. Pregnancies were included in which women were exposed to an AED between January 2003 and December 2012 either preconceptionally or during the first trimester. Binary logistic regression analysis was used to compare the proportion of various AEDs annually. Dependent variable was the year in which conception took place; the AED and type of epilepsy were covariates. In addition, the mean number of concomitantly used AEDs were calculated per year and analyzed by ANOVA. Results: A total number of 1,733 pregnancies in were included in the analysis. The proportion of use of levetiracetam and lamotrigine showed an upwards trend from 6.2 and 16.0% in 2003 till 25.0 and 33.5% in 2012, with corresponding adjusted Odds Ratio (OR) of 4.89 (95% CI 2.65-9.06) and 2.77 (95% CI 1.76-4.34) respectively. The proportion of use of valproate and carbamazepine decreased from 28.4 and 28.4% in 2003 till 9.3 and 17.3% in 2013, with an adjusted OR of 0.28 (95% CI 0.16-0.48) and from 0.44 (95%CI 0.28-0.70) respectively. The use of other miscellaneous AEDs decreased from 20.9% to 14.9%, OR 0.61 (95%CI 0.38-0.98). The average number of AEDs being used was 1.30 in 2003 and 1.24 in 2012 (p>0.05). Conclusions: The use of relatively safer AEDs gradually increased over the past 10 years compared to drugs more frequently associated with congenital defects. The mean number of AEDs used remained stable of the years. Our findings are in line with advice provided in the literature on the use of AEDs.