Animal Studies

Commonly Used Chinese Medicines - Adverse Outcomes

A recent comprehensive preclinical study to overview the safety of those commonly used Chinese medicines during pregnancy showed that the adverse pregnancy outcomes in mice at clinical doses were very common (Wang et al., 2012). The top 20 most commonly used Chinese medicines for pregnancy were selected, and the crude extract was administered to pregnant mice at clinical doses during five different gestational stages, namely implantation, gastrulation, organogenesis, maturation, and whole gestation periods. Maternal side effects, including weight loss, litter reduction, implantation failure, and fetal resorption; and perinatal effects on growth restriction, developmental delay, congenital malformations, and postnatal mortality, were compared. Although the study was performed in only one specie and the maximum sample size was small as pointed out by a re-evaluation study, the study did raise potential safety concern of Chinese herbal medicines in pregnancy. Direct dose-dependent relationship in the in vivo study is not expected since in vivo settings involve complicated bioavailability and metabolism which is controlled in in vitro settings. On the other hand, susceptibility of adverse outcomes may vary in different gestational periods due to massive dynamic changes of physiological, biochemical and pharmacological parameters during the pregnancy. References: Wang CC, Li L, Tang LY, Leung PC. 2012. Safety evaluation of commonly used Chinese herbal medicines during pregnancy in mice. Hum Reprod 27, 2448-2456.