Untreated epilepsy and pregnancy

PURPOSE: Untreated pregnant women with epilepsy (WWE) are not readily available for study. We present data accumulated in the Australian Pregnancy Register (APR) between 1999 and March 2025, concerning the risk of foetal structural malformation (FM) and the maintenance of freedom from seizures in pregnant WWE, untreated. METHODS: APR contained records of 2826 pregnancies in Australian WWE since 1999. Of these, 69 ASM-treated ones had ended in spontaneous abortions. Of the remaining 2757 pregnancies, 2538 had been treated with antiseizure medication (ASM) therapy continuously throughout pregnancy, 219 had commenced pregnancy untreated. Of these 219, ASM treatment had recommenced in 91 during pregnancy while 128 (58.5%) remained untreated with ASMs throughout pregnancy. RESULTS: The occurrence rate for a malformed foetus (FM) in the ASM-untreated pregnancies tended to be lower than in the ASM-treated pregnancies (R.R. = 0.48, 95% C.I. 0.23, 1.00). Seizure freedom occurrence rates throughout pregnancy were not statistically significantly different (R.R. = 0.90, 95% C.I. 0.82, 1.08). CONCLUSIONS: The outcomes of the presence or absence of ASM therapy during pregnancy were not statistically significantly different in relation to the occurrences of seizure freedom and FM but the lower occurrence of FM in the untreated pregnancies was at the P < 0.05 significance threshold. The number of FM encountered was small so that statistically significant findings were unlikely. Seizures occurring during pregnancy were an appreciable factor in restarting ASM therapy. Trends found in the study, interpreted cautiously, may be helpful in future treatment management decisions.