Safety and efficacy of blue cohosh (Caulophyllum thalictroides) during pregnancy and lactation.

BACKGROUND There is a lack of basic knowledge on the part of both clinicians and patients as to the indications for use and safety of herbal medicines in pregnancy and lactation. This is one article in a series that systematically reviews the evidence for commonly used herbs during pregnancy and lactation. OBJECTIVES To systematically review the literature for evidence on the use, safety and pharmacology of blue cohosh, focusing on issues pertaining to pregnancy and lactation. METHODS We searched 7 electronic databases and compiled data according to the grade of evidence found. RESULTS According to a survey of midwives in the United States, approximately 64% of midwives reported using blue cohosh as a labour-inducing aid. There are three case reports in the scientific literature that blue cohosh taken at the time of delivery may cause; 1) perinatal stroke, 2) acute myocardial infarction, profound congestive heart failure and shock and 3) severe multi-organ hypoxic injury. There is one case report that blue cohosh possesses abortifacient properties. There is in vitro evidence that blue cohosh may have teratogenic, embryotoxic and oxytoxic effects. In lactation, the safety of blue cohosh is unknown. CONCLUSIONS Based on the available scientific information, blue cohosh should; 1) be used with extreme caution during pregnancy, 2) be used only under medical professional supervision and 3) not be available to the public as an over-the-counter product. There is an urgent need to conduct a retrospective or prospective cohort study of midwifes using blue cohosh in order to determine its safety. Key words: Blue cohosh, caulophyllum thalictroides, pregnancy, lactation, breastfeeding, systematic review.