Herb
PREGNANCY RECOMMENDATION: Contraindicated
BREASTFEEDING RECOMMENDATION: Contraindicated
PREGNANCY SUMMARY
No reports describing the use of arnica in human pregnancy have been located. The herb should not be used in pregnancy as it is a uterine stimulant that has been used traditionally as an abortifacient (1).
FETAL RISK SUMMARY
Arnica is a perennial plant that has bright yellow, daisy-like flowers that, when dried, are the primary parts used, but the roots and rhizomes also are used. The herb has been used medicinally for hundreds of years, especially in Europe. The herb and its extracts have been used as a topical treatment for skin conditions and wounds and are often used in cosmetic formulations. However, clinical evidence to support its use as an anti-inflammatory or analgesic is lacking. The FDA has classified arnica as an unsafe herb when used orally, in which case it is considered a poison, or applied to broken skin where absorption could occur. It is possibly safe when used in amounts commonly found in foods. A large number of chemicals are found in arnica, including flavonoids glycosides, isomeric alcohols, terpenoids (including sesquiterpene lactones), amines, coumarins, carbohydrates, volatile oils, fatty acids, and other compounds. The active ingredients are the sesquiterpene lactones (1–3).
No carcinogenicity, reproductive, or developmental toxicity data are available (3).
In homoeopathic formulations, arnica has been promoted for use before and during labor as helpful for internal and external bruising of both the mother and newborn infant (4). In a survey of 1044 Italian women, 491 (47%) reported that they had taken or were taking one or more herbals in the last year, sometimes during pregnancy (5). Arnica was among the top 10 herbs taken by the women.
BREASTFEEDING SUMMARY
Although it has not been studied, an abstract describing toxicity in a nursing infant suggests that some of the chemicals in arnica are excreted into human milk. A 9-day-old term male infant who was exclusively breastfed presented with a 1-day history of lethargy, decreased milk intake, anemia, and jaundice (6). The mother, who was asymptomatic, had started drinking a tea made from arnica flowers 48 hours before the onset of symptoms. No reason for the infant’s jaundice was found on workup. A screening test in the infant for glucose-6-phosphate dehydrogenase (G6PD) was normal. Exchange transfusions were used to lower the bilirubin and correct the infant’s anemia. The mother stopped drinking the tea and resumed breastfeeding, and no further hemolysis or other problems were noted in the infant (6).
References
1.Arnica. The Review of Natural Products. St. Louis, MO: Wolters Kluwer Health, 2010.
2.Arnica. Natural Medicines Comprehensive Database. 10th ed. Stockton, CA: Therapeutic Research Faculty, 2008:83–5.
3.Anonymous. Final report on the safety assessment of arnica montana extract and arnica montana. Int J Toxicol 2001;20(Suppl 2):1–11.
4.Kaplan B. Homoeopathy: 2. In pregnancy and for the under-fives. Prof Care Mother Child 1994;4:185–7.
5.Zaffani S, Cuzzolin L, Benoni G. Herbal products: behaviors and beliefs among Italian women. Pharmacoepidemiol Drug Saf 2006;15:354–9.
6.Miller AD, Ly BT, Clark RF. Neonatal hemolysis associated with nursing mother ingestion of arnica tea (abstract). Clin Toxicol 2009;47:726.