Epilepsy is the most common, neurological condition requiring treatment during pregnancy, and treatment must weigh the risk of epilepsy against the risk of drug side effects. The use of antiepileptic drugs during pregnancy has been associated with pregnancy complications, including pre-eclampsia, hemorrhage, preterm delivery, intrauterine growth retardation and malformations. However, the relationship between antiepileptic drugs and spontaneous miscarriage or stillbirth is not known. Therefore, researchers from Aarhus University conducted a population-based cohort study to investigate the association between the use of antiepileptic drugs during pregnancy and spontaneous miscarriage or stillbirth. The results of the study were published in the August 22 issue of BMJ. A total of 983,305 pregnant women from the Danish Medical Birth Register and the Danish National Hospital Discharge Register between February 1997 and December 2008 were included in the study, and information on the use of antiepileptic drugs was obtained through the Danish Drug Use Registry. Risk ratios for spontaneous abortion or stillbirth after antiepileptic drug use during pregnancy were analyzed by binomial regression, correcting for potential confounders, including maternal age, income, education, history of severe mental disorders, and history of substance abuse. The results showed that a total of 4700 (0.5%) pregnant women used antiepileptic drugs during pregnancy. After correcting for potential confounders, the risk of spontaneous abortion was 13% higher in pregnant women using antiepileptic drugs than in those not using antiepileptic drugs. However, stratification of maternal status epilepticus revealed that the risk of spontaneous abortion increased only among pregnant women without a diagnosis of epilepsy and did not change among pregnant women with confirmed epilepsy. Eighteen stillbirths occurred in women who used antiepileptic drugs during pregnancy, suggesting no correlation, but with less statistical precision. The study suggests that the use of antiepileptic drugs during pregnancy does not increase the risk of spontaneous abortion in women who develop epilepsy. The data support continued treatment with antiepileptic drugs during pregnancy in women with epilepsy because of the low risk of fetal death. However, the use of higher doses of antiepileptic drugs in pregnant women with epilepsy may increase the risk of spontaneous abortion, especially with high doses of sodium valproate, clonazepam, and carbamazepine.