This study is a review of the literature on the influence of epilepsy and antiepileptic medication on the course of pregnancy and the foetus, as well as of the effect of pregnancy on the disease. Antiepileptic treatment is supposedly responsible for the increased rate of abnormal bleeding after delivery. Data on the perinatal mortality of epileptics are conflicting. The offspring of epileptic women are often smaller than normal neonates, indicating retarded growth, and the incidence of malformations is 1.25 times higher. Until now there has been no direct evidence of a teratogenic effect of the commonly used antiepileptic drugs, and the risk of malformations may possibly be correlated with the severity of the epilepsy. The effect of pregnancy on seizure frequency seems to be quite variable. Higher seizure frequency is seen during pregnancy, but this is not a universal phenomenon. The incidence of seizures in gestational epilepsy has no predictive value with respect to the course of later pregnancy. A positive correlation seems to exist between the development of eclampsia and later epilepsy, a family history of epilepsy and cerebral dysrhythmias. Status epilepticus is uncommon in pregnancy. The requirement of several antiepileptic drugs is increased during pregnancy. The metabolism of carbamazepine, primidone, and clorazepate is probably accelerated in the gestational period, but data on other antiepileptic drugs are inconclusive or lacking. The intestinal absorption of antiepileptic drugs may be impaired during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)