Most proprietary Chinese medicines have no effect on pregnancy. However, proprietary Chinese medicines have many ingredients and a rich content of active ingredients, often without clinical trials, and the ingredients in the medicines are not categorized by the FDA, so some of the active ingredients may have an effect on the development of the fetus during pregnancy. Western medicines can be categorized by the FDA as A, B, C, D, or X. The categorization will be based on the effects on the embryo of each drug after animal testing and human testing. Proprietary Chinese medicines are often not categorized in this way, so they must be used with caution, especially by reading the instructions, and if the instructions already mention that they are prohibited for pregnant women, they should not be used.