The main concerns associated with epilepsy during pregnancy consist of maternal and fetal risks from uncontrolled seizures, and harmful effects of the treatment on the development of the offspring. Although seizure control is maintained in the majority, worsening occurs in a fraction of childbearing women with epilepsy. As multiple factors associated with pregnancy may have a negative impact on epilepsy, a careful analysis of the situation should be performed in those who deteriorate. Emotional and behavioural influence, including insufficient sleep and treatment non-compliance, as well as physical factors, such as emesis and pelvic distortion, should receive attention. The serum concentrations of almost all antiepileptic drugs decrease during pregnancy, particularly those which are metabolised by glucuronidation. The inter-individual variability is pronounced. In highly protein-bound drugs, such as phenytoin and valproate, unbound drug is less affected than total concentrations. Lamotrigine and levetiracetam concentrations may decrease by more than 50% in the course of pregnancy; monohydroxyoxcarbazepine by up to 30-40%. Appropriate clinical follow-up tailored to individual needs and supported by therapeutic drug monitoring should be performed in pregnant women with epilepsy. Education concerning reproductive issues is an essential part of the epilepsy service to fertile women.