Abstracts

Older generation antiepileptic drugs (AEDs) such as carbamazepine, phenytoin and valproate are associated with a risk for teratogenicity and is a major concern for pregnant women with epilepsy treated with these AEDs. Current clinical experience with the newer generation AEDs including oxcarbazepine on pregnancy outcomes is limited. This study is currently being conducted to assess pregnancy outcomes in pregnant women with epilepsy treated with various AEDs with a focus on those patients taking oxcarbazepine.
A comprehensive study to evaluate the outcome of pregnancies of women who were treated with oxcarbazepine or other AEDs during pregnancy is underway in Finland. Approximately 37,000 subjects approved as eligible for reimbursement for AEDs by the Social Insurance Institution of Finland for the first time between 1985 and 1994 were identified. A reference cohort of persons residing in Finland at the time of the reimbursement approval was identified from the Finnish Population Registry. The control cohort is of similar size with frequency-matching on age, sex, and municipality of residence. Information on pregnancies and births in women with epilepsy during the years 1991-2000 was obtained from the national Medical Birth Registry. The patient files of the women from this pilot patient sample were reviewed by an experienced study nurse to obtain data on AEDs during pregnancy and pregnancy outcomes.
A random sample of 779 pregnancies was obtained from the epilepsy cohort and was reviewed. Of these, 296 women (38.0 %) were not receiving AEDs during pregnancy, 378 (48.5 %) were on monotherapy, and 105 (13.5 %) on polytherapy. Forty-two of these patients received oxcarbazepine during their pregnancies, 30 on monotherapy and 12 in combination with other AEDs. No malformations were recorded in the oxcarbazepine monotherapy group and 1/12 (1%) was observed with oxcarbazepine in combination with valproate. This woman had delivered two normal infants previously while receiving oxcarbazepine monotherapy. Fetal malformations were observed in 13/89 (14.6 %) of pregnancies in women receiving valproate monotherapy, 10/225 (4.4 %) of pregnancies in women on carbamazepine monotherapy.
In this review, oxcarbazepine during pregnancy was not associated with fetal malformations. Although these observations are encouraging, the patient sample size was small. Thus, this study is ongoing and will review the approximately 2,500 pregnancies in the Finnish national epilepsy cohort from 1991-2000.
[Supported by: Novartis]