How does blue cohosh cause miscarriages?

Causes contractions: Wisdom says: avoid this in most all cases. There are certainly some who know how to make good use of ancient herbal therapies, but very few. This is powerful stuff and quite toxic. Action is complex, but vaso-constriction is part of it. It induces labor regardless of the readiness of the fetus. Steer clear or be prepared for facing a medical emergency.