Blue cohosh linked to stroke: side effects of some herbs harmful in pregnancy.(Obstetrics)

NEW YORK -- Many herbal preparations taken during pregnancy are innocuous, but some are ineffective, and others are downright dangerous, Dr. Tieraona Low Dog said at a meeting on botanical medicine sponsored by Columbia University and the University of Arizona.

Blue cohosh used to stimulate labor, should be wholly avoided in pregnancy. Blue cohosh is often combined with black cohosh and taken as a uterine tonic or partus preparator during the last 6 weeks of pregnancy, according to Dr. Low Dog of the University of New Mexico, Albuquerque.

Blue cohosh was listed in the U.S. Pharmacopeia for labor induction at the end of the 19th century. It is still widely prescribed by lay midwives, and, in one survey, 90 of 174 (52%) certified nurse-midwives said they recommended labor-stimulating preparations; of these, 64% used blue cohosh, and 45% used black cohosh.

Complications, which were reported by 21% of respondents who used either black or blue cohosh, included transient fetal tachycardia, meconium-stained fluid, and nausea.

Blue cohosh contains compounds that exhibit cardiotoxic, vasoconstricting, and uterine-stimulating activity, Dr. Low Dog said.

Cases involving stroke, cardiomegaly, and pulmonary edema have been reported in infants of mothers who took blue cohosh during pregnancy. "Leave this herb alone," she said.

Probably the herb most commonly taken by pregnant women in the United States and Europe is raspberry leaf, which is often prepared as a "pregnancy tea." It is believed to alleviate morning sickness, prevent miscarriage, and aid in childbirth.