Red Clover, Cautions
Due to its phytoestrogen content some herbalists recommend avoiding red clover during pregnancy.
- may feel too relaxing for very lax tissues
- not ideal when heat needs strong movement
- softening may be too gentle for sharp, acute heat
Red Clover is best when heat is held — not when tissues are already loose.
Adverse reactions
Ingestion of large amounts of clover in animal feed has been associated with a number of adverse effects in sheep in Australia. A publication on “clover disease” described symptoms of infertility, abnormal lactation, dystocia and prolapsed uterus, all of which were hypothetically attributed to the estrogenic effects of isoflavones. None of the controlled, clinical trials has reported adverse effects at doses up to 160 mg of isoflavones per day. Trifolium pratense does not contain coumarins, and therefore the concerns about blood coagulation are unfounded.
Case Reports:
Subdural hematoma: In a 65-year-old woman with no other risk factors for bleeding except long-term use of red clover supplements for postmenopausal symptoms. After postoperative re-hemorrhage, an intraoperative thromboelastogram confirmed that antiplatelet effects were more likely than coumarin toxicity. There was no further bleeding after the patient was subsequently treated with tranexamic acid and platelet transfusions .
Acute-on-chronic subdural hematoma in a patient taking Red Clover herbal supplement: A case report
Subarachnoid hemorrhage: In a 53-year-old woman following use of an herbal supplement containing red clover, dong quai, and Siberian ginseng for perimenopausal hot flashes. Symptoms resolved after supplement discontinuation
Contraindications
Contraindicated in cases of hypersensitivity or allergy to the crude drug. It is also contraindicated during pregnancy, breastfeeding and for children under the age of 12 years, and in cases of hormone associated diseases, due to the potential hormonal effects.
Warnings
Due to the potential estrogenic effects of the crude drug, patients with hormone-related disorders, estrogen-dependent cancers or a familial history of estrogen-dependent cancers should contact a health care provider before use.
Drug interactions
There are conflicting data concerning an interaction of the crude drug with tamoxifen and other antiestrogenic drugs. Some studies suggest that specific isoflavones may enhance the ability of tamoxifen to inhibit the growth of estrogen-receptor-positive breast cancer cells . In rodent models, genistein has been shown to inhibit the efficacy of tamoxifen on the growth of estrogen-receptor-positive breast cancer cells implanted in ovariectomized mice, while other research shows that specific isoflavones may be additive and work in a synergistic manner to prevent the development of chemically induced tumors and the growth of existing tumors . Therefore, the use of the crude drug or its preparations is not recommended in those being treated with tamoxifen and other antiestrogenic drugs until further research has been done.
Red clover may increase effects of anticoagulants and antiplatelet drugs . Potential interactions between alternative therapies and warfarin
Red clover causes toxic effects when used with methotrexate. . Red clover causing symptoms suggestive of methotrexate toxicity in a patient on high-dose methotrexate.