Background The use of complementary and alternative medicines (CAM) is growing in the general population. Herbal medicines are used in all countries of the world and are included in the top CAM therapies used. Methods A multinational study on how women treat disease and pregnancy-related health ailments was conducted between October 2011 and February 2012 in Europe, North and South America and Australia. In this study, the primary aim was to determine the prevalence of herbal medicine use in pregnancy and factors related to such use across participating countries and regions. The secondary aim was to investigate who recommended the use of herbal medication in pregnancy. Results There were 9,459 women from 23 countries participating in the study. Of these, 28.9% reported the use of herbal medicines in pregnancy. Most herbal medicines were used for pregnancy-related health ailments such as cold and nausea. Ginger, cranberry, valerian and raspberry were the most commonly used herbs in pregnancy. The highest reported rate of herbal use medicines was in Russia (69%). Women from Eastern Europe (51.8%) and Australia (43.8%) were twice as likely to use an herbal medicine versus other regions. Women using herbal medicines were characteristically having their first child, non-smokers, using folic acid and consuming some alcohol in pregnancy. Also, women who were currently students and women with an education other than a high school degree were more likely to use herbal medicines than other women. Although 1 out of 5 women stated that a physician had recommended the herbal use, most women used herbal medicine in pregnancy on their own initiative. Conclusions In this multinational study herbal medicine use in pregnancy was high although there were distinct differences in the herbs and users of herbal medicines across regions. Most commonly the women self-medicated with herbal medicine to treat pregnancy-related health ailments. More knowledge regarding the efficacy and safety of herbal medicines in pregnancy is warranted.