Pregnant women with epilepsy have greater risk of complications and death during delivery, a new study suggests.

Women with epilepsy who become pregnant account for an exceedingly small number of pregnancies overall – just 0.3 to 0.5 percent – but they are at an increased risk of dying or suffering complications such as preeclampsia (a dangerous form of high blood pressure), preterm labor, and stillbirth.

Harvard researchers analyzed 4.2 million records of pregnancy cases that included 14,151 women with epilepsy. Nationwide, this represented 69,385 women with epilepsy and about 20.4 million women without epilepsy in more than 20.5 million total discharges.

The authors found that women with epilepsy had a risk of death during delivery hospitalization of 80 deaths per 100,000 pregnancies, which is higher than the 6 deaths per 100,000 pregnancies found among women without epilepsy, according to the study, which appears online in JAMA Neurology.

The authors cautioned, however, that the study lacked information on the cause of death during delivery among women with epilepsy. They also noted that, while the risk of dying during delivery is higher, the death of a mother during delivery is still very rare even among women with epilepsy.