Herbal Medicines—Are They Effective and Safe during Pregnancy?

Since the teratogenicity of Thalidomide has been proven, herbal products are more commonly used in pregnancy to not only relieve morning sickness but also to fight infections. These products are frequently considered as natural and therefore harmless. However, herbs contain a number of active substances that, when used during pregnancy, can affect the development of the fetus. Often, pregnant women do not consult the usage of herbal medicines with a physician. The access to these products is easy and treatment of certain ailments with the use of herbs is common in many countries. The aim of the present literature review was to discuss available data regarding the efficacy and safety of cranberry, chamomile, Echinacea purpurea, garlic, ginger, Ginkgo biloba, and peppermint, which are used to counteract the most common ailments during pregnancy, i.e., infections and pregnancy-related ailments (e.g., nausea and vomiting, dizziness, and headache). Analysis of available data showed that ginger is one of the most extensively analyzed herbal remedies. The dose of ginger below 1000 mg per day may help to relief hypereremesis gravidarum, and such an amount of ginger did not increase frequency of adverse effects for either woman or developing fetus. Data regarding other herbs are most often heterogeneous and give conflicting results with no clear conclusions. However, all herbal products should be used with a special caution in pregnancy. Further high-quality human studies should be determined to confirm the safe doses of herbal products which could be used by pregnant or breast-feeding women.