Safety evaluation of commonly used Chinese herbal medicines during pregnancy in mice.

BACKGROUND It is unclear how safe the use of Chinese herbal medicine is during pregnancy and if the herbal medicines do any harm to pregnancy, embryo-fetal development and prenatal and post-natal growth. A large-scale preclinical study was conducted to detect the adverse effects of Chinese herbal medicines during pregnancy. METHODS Twenty of the most commonly used Chinese herbal medicines prescribed for pregnancy were selected and the crude extract was administered to pregnant mice at clinical doses during five different gestational stages, namely post-implantation, gastrulation, organogenesis, maturation and whole gestation periods. Maternal effects on side effects, weight loss, litter reduction, implantation failure and fetal resorption and perinatal effects on growth restriction, developmental delay, congenital malformations and post-natal mortality were determined. RESULTS Adverse pregnancy outcomes were commonly observed after maternal exposure to the herbal medicines, particularly during early pregnancy. Major events included maternal and perinatal mortality were recorded. Maternal weight gain, embryo growth and post-natal weight gain were significantly decreased. Fetal resorption and skeletal malformations were significantly increased. CONCLUSIONS Reproductive toxicity of Chinese herbal medicines commonly used during pregnancy was identified in mice. Caution should be taken in the clinical use of herbal medicines during pregnancy.