Effects of Taking Herbal Medicines in Early Gestation on Pregnancy and Placental Formation

The use of Japanese herbal medicines (Kampo medicines), rooted in centuries of traditional practice, lacks extensive Western scientific validation regarding their safety. Concerns include potential risks such as placental dysplasia, miscarriage, teratogenicity, and fetotoxicity when administered to pregnant women. Therefore, scientific safety evaluations are crucial for the appropriate use of Kampo medicines during pregnancy. Critical physiological processes such as implantation, invasion into the endometrium, placentation, and fetal development are vital for establishing a successful pregnancy. The placenta, forming from implantation until birth, is essential for fetal growth and nutrition. Proper placental function relies on the regulated differentiation and development of specific trophoblast cell lineages. If Kampo medicines impact these cell lineages, there may be increased risks of fetal developmental issues and pregnancy complications. current studies often neglect evaluating placental function or formation, focusing primarily on fetal toxicity and teratogenicity. Thus, assays for placental function and placentation toxicity are needed. This review consolidates existing knowledge on the effects of Kampo medicines, herbs and herbal medicines on pregnancy and placentation, emphasizing the necessity for scientific safety assessments to guide their use during pregnancy. Ensuring accurate information and safety of Kampo medicines, herbs and herbal medicines for pregnant women is essential to safeguard the health of the mother, fetus, and placenta.