New research has shown the risk of complications in pregnancy could be increased by the use of anti-epileptic drugs.
Conditions such as pre-eclampsia could be increased by using standard drugs available on the UK market.
The study in Norway analysed 2,805 women with a history, or current condition, of epilepsy, and 362,302 women without the condition.
Of those women with epilepsy, 34% were taking anti-epileptic drugs.
The study found women using the drugs were exposed to an increased risk of delivery before 34 weeks, mild pre-eclampsia and vaginal bleeding late in pregnancy.
The research, published in BJOG: An International Journal of Obstetrics and Gynaecology, found there was no increased risk to women with epilepsy who were not using anti-epileptic drugs.
"Pregnant women with epilepsy using anti-epileptic drugs had a 1.5-fold increased risk of mild pre-eclampsia, a nearly two-fold increased risk of late vaginal bleeding, a 1.5-fold increased risk of gestational hypertension and delivery before week 34," the researchers revealed.