O-31 Antiepileptic drug (aed) exposure in pregnancy and pregnancy outcome from national drug usage data

Abstract

Background Antiepileptic drugs (AEDs) taken during pregnancy are known to increase the risk of fetal malfor-mations and potentially affect the neurodevelopment in children exposed. This study aimed to investigate the use of AEDs by pregnant women and women during their childbearing years in New Zealand and the association between AED use and rates of pregnancy termination, spontaneous abortion and stillbirth. Methods Retrospective population based cohort study using administrative databases in New Zealand between 2008 and 2014. Women who had been pregnant were identified by the National Minimum Dataset and were linked to the Pharmaceutical Collection to obtain infor-mation on use of AEDs. Women aged between 15 and 45 years dispensed AEDs were identified in the Pharmaceu-tical Collection. Results There was a significant increase in the number of women of child-bearing potential prescribed AEDs, from 9 women per 1000 women in 2008 to 11.4 wom-en per 1000 women in 2014. Use of the older generation AEDs declined over the time period while use of the newer generation AEDs increased. General practitioners provided 60% of the prescriptions of AEDs to women of child-bearing potential. Women who had been dis-pensed an AED had an increased rate of spontaneous abortion and pregnancy termination compared to those not dispensed an AED, 13.16 spontaneous abortions per 100 pregnancies, compared with, 8.00 per 100 pregnancies (risk ratio 1.64, 95% CI 1.50 to 1.80), and 21.29 terminations per 100 pregnancies compared with 19.50 per 100 pregnancies (risk ratio 1.09, 95% CI 1.02–1.17). Conclusion Use of newer AEDs is increasing in women of child-bearing potential in New Zealand leading to an overall increase in AED use in this group despite a fall in the use of older AEDs. AED use is this study was associat-ed with an increased risk of spontaneous abortion and increased rate of pregnancy termination.