Objective To report the complications during pregnancy and delivery in women with epilepsy, compared with a control group without epilepsy, with special focus on potential risk factors, such as epilepsy severity and dosage of antiepileptic drugs.Design Hospital-based retrospective study.Setting Data from pregnancy notification forms and hospital case records.Population Women with a past or present history of epilepsy (n = 205) delivered in Bergen, Norway, in the period 1999-2006, and a matched control group of women (n = 205) without epilepsy.Methods Data were compared and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by multiple logistic regression models.Main outcome measures Pre-eclampsia (mild and severe), gestational hypertension, vaginal bleeding (early and late), caesarean section, vaginal operative delivery, postpartum haemorrhage and major malformations.Results Women with epilepsy using antiepileptic drugs had an increased risk of severe pre-eclampsia (OR, 5.0; 95% CI, 1.3-19.9), bleeding in early pregnancy (OR, 6.4; 95% CI, 2.7-15.2), induction (OR, 2.3; 95% CI, 1.2-4.3) and caesarean section (OR, 2.5; 95% CI, 1.4-4.7) adjusted for maternal age, parity, education, smoking, medical conditions and body mass index ‡30 kg/m 2 . There was also an increased risk of malformations in the offspring (OR, 7.1; 95% CI, 1.4-36.6). Women without antiepileptic drug use had increased risks of forceps delivery and preterm birth. Active epilepsy (seizures during the last 5 years) versus nonactive epilepsy did not discriminate for any of these complications; 84.5% of women with epilepsy and antiepileptic drug use were using folate.Conclusion Women with epilepsy using antiepileptic drugs had an increased risk of pregnancy and delivery complications, whereas women not using antiepileptic drugs had few complications. Seizures, high doses of antiepileptic drugs, obesity and lack of folate could not explain these increased risks.Keywords Antiepileptic drugs, delivery, epilepsy, pregnancy.Please cite this paper as: Borthen I, Eide M, Daltveit A, Gilhus N. Obstetric outcome in women with epilepsy: a hospital-based, retrospective study. BJOG 2011;118:956-965.