Is blue cohosh safe during pregnancy?

What does the evidence say about blue cohosh during pregnancy?

1. Blue cohosh contains N-methylcytisine, which has nicotine-like effects, and caulosaponin, a glycoside that constricts coronary vessels, and the LactMed database recommends strongly against its use during breastfeeding because of the lack of safety data and its potential for toxicity. 1
2. The toxic saponins and alkaloids in blue cohosh impair mitochondrial function by disrupting cell membranes, and researchers point to this as the likely mechanism behind its cardiotoxic effects in newborns, despite roughly 64% of surveyed midwives reporting use of it for labor induction. 2
3. Published case reports describe newborns whose mothers used blue cohosh for labor induction developing acute heart attack with profound congestive heart failure and shock, perinatal stroke, and severe multi-organ hypoxic injury, leading researchers to identify blue cohosh as a potent teratogen. 3
4. NIH's center for complementary health is explicit that black cohosh and blue cohosh are different herbs, and it separately warns that blue cohosh may cause high blood pressure, high blood sugar, and chest pain, with use to induce labor tied to life-threatening complications in the infant. 4
5. No data exist on the safety or effects of blue cohosh in nursing mothers or infants, and LactMed notes it has no established uses during breastfeeding. 1

Is blue cohosh safe in each trimester?

• First trimester. Blue cohosh isn't traditionally used this early, since its main use is labor induction near term. If you see it listed in any early-pregnancy herbal blend, skip it and flag the ingredient to your provider.
• Second trimester. The same avoidance holds. "Labor prep" teas and tinctures sold for later use sometimes include blue cohosh, so check ingredient lists before starting any late-pregnancy herbal routine.
• Third trimester. This is when blue cohosh is traditionally used to try to bring on labor, and it's exactly when the documented newborn harms occurred in case reports. Avoid it even if a home-birth guide or labor-support source recommends it.