Herbal medicines and pregnancy: A narrative review and anaesthetic considerations

The use of herbal medicines by pregnant women varies among different countries, ranging from 4.3% in Sweden to 69% in Russia. The aim of this narrative review is to evaluate the benefits and safety of common herbal medicines used during pregnancy. A systematic literature search (from 1995 to February 2018) was performed using a variety of electronic databases. The levels of evidence of the clinical studies were graded using the Oxford Centre for Evidence-Based Medicine levels of evidence guidelines. From the 736 articles retrieved, 69 articles were used for this review. Ginger has been investigated extensively and has been consistently found to decrease nausea and vomiting associated with pregnancy (Level 2). There is insufficient evidence concerning the efficacy of other herbal medicines such as garlic, cranberry and raspberry in pregnancy (Level 3-4). Much of the literature is based on case reports with limited pharmacodynamic/kinetic studies. There are no clear data on the adverse herb-drug interactions during anaesthesia. As the risks of these interactions are unknown, it would be prudent for anaesthetists to explicitly ask their patients about their use of herbal medicines before surgery and prior to labour and birth. The European Society of Anaesthesiology and American Society of Anesthesiologists recommend that patients cease taking herbal medicines two weeks before surgery.