Herb
PREGNANCY RECOMMENDATION: Limited Human Data—No Relevant Animal Data
BREASTFEEDING RECOMMENDATION: No Human Data—Potential Toxicity
PREGNANCY SUMMARY
Echinacea is an ancient preparation that has recently undergone resurgence in use. Use during pregnancy creates the potential for exposure of the embryo and fetus to multiple chemical compounds that have not undergone reproductive toxicity testing in animals or humans. Moreover, standardization of any herbal product as to its constituents, concentrations, and the presence of contaminants are generally lacking. Two sources recommend that parenteral administration of the herb (a product form not available in the United States) should not be used in pregnancy (1,2). Another source states that echinacea should be avoided during pregnancy because of the lack of information (3). There is only one published report describing human pregnancy exposure. Although this study found no increased risk for major malformations, it was limited by its small sample size, the self-selection of the study group, and the lack of dose standardization (4). Thus, the safety of echinacea products during pregnancy remains to be established and, until such additional evidence is published, pregnant women should be counseled of such.
FETAL RISK SUMMARY
The traditional uses of echinacea are topically to enhance wound healing and systemically as an immunostimulant (5). It was used by the Native Americans before colonization of the continent and was a common medicine in the United States in the late 19th and early 20th centuries (6). The herb is available orally as capsules, as expressed, fresh juice, and as tinctures. In Germany, an intravenous preparation is also available (7). Specific indications for systemic echinacea listed in one publication are prophylaxis and treatment of viral upper respiratory tract infections and combined with conventional anti-infective agents in the treatment of more severe infections (6). Specific topical indications listed are the treatment of eczema, psoriasis, and herpes simplex. Another publication lists antiseptic and antiviral indications (8).
Echinacea angustifolia, the plant most commonly used for medicinal purposes, is a perennial herb of the Compositae family that grows to a height of 3 feet, terminating in a single colorful flower head. The plant is indigenous to the central United States. Related species that have been used in traditional medicine include E. purpurea and E. pallida (5,9). Because E. angustifolia and E. pallida closely resemble each other, preparations of echinacea may be mislabeled or contain mixtures of the two species. German authors recommend the use of the above-ground parts (not the roots) of E. purpurea or the roots of E. angustifolia for medicinal purposes (9).
The principal anti-inflammatory and immunostimulant compounds are found in the hydrophilic and lipophilic fractions of the root, leaves, and flowers (5,6). The specific active ingredients accounting for the medicinal effects of the herb have not been identified. The water-soluble polysaccharides in the roots, however, appear to be a major component of the anti-inflammatory and immune-stimulating properties (6). Essential oil from the root also contains unsaturated alkyl ketones and isobutylamides. Although not all components from the various parts of the plant have been identified, the chemical compounds that have been isolated include echinacoside (a caffeic acid glycoside), a volatile germacrene alcohol (not usually found in dried plant material), echinacein (an isobutylamide responsible for the pungent odor), echinacin B, chicoric acid, cyanrine, chlorogenic acid, caftaric acid, (z)-1,8-pentadecadiene (also known as Z-pentadeca-1,8-diene), and arabinogalactan (5,6).
No animal studies examining the reproductive effects of any of the species of echinacea or their components have been located. One prospective report, however, described the use of this herb in human pregnancies (4). Between 1996 and 1998, 206 women contacted a teratogen information service regarding their exposure to echinacea products (primarily E. angustifolia and E. purpurea) during gestation. Of these, 112 used echinacea during the 1st trimester. The total cohort was disease matched to 206 women exposed to nonteratogenic agents by maternal age, alcohol, and cigarette use. There were three sets of twins in the study group and none in the control group. Both groups were followed prospectively to determine pregnancy outcomes. No statistically significant differences between the study and control women were found for the following outcomes: live birth (94.7% vs. 96.1%), spontaneous abortion (6.3% vs. 3.4%), induced abortion (0.5% vs. 0.5%), vaginal delivery (83.1% vs. 81.3%), maternal weight gain (15.2 vs. 14.4 kg), gestational age at delivery (39.2 vs. 39.2 weeks), birth weight (3466 vs. 3451 g) (excluding twins), fetal distress (23.6% vs. 21.1%), major malformations (in total group) (3.6% vs. 3.5%), and minor malformations (3.6% vs. 3.5%). Among the 98 newborns exposed during the 1st trimester, there were four (4.1%) major defects: left inguinal hernia requiring surgical repair; bilateral hydronephrosis; syndactyly of the second and third toes; and duplicate left renal pelvis. The authors concluded that there was no increased risk for major anomalies (4).
An in vitro study using E. purpura reported adverse effects in human sperm (10). In a sperm penetration assay, zona-free hamster oocytes were incubated for 1 hour with two concentrations of E. purpura, 0.8 and 8 mg/mL, dissolved in HEPES-buffered synthetic human tubal fluid (modified HTF). Fresh human donor sperm was suspended in the modified HTF and then mixed with the oocytes for 3 hours. Modified HTF served as the control. At the 0.8 mg/mL concentration, 5 of 9 (56%) of the oocytes were penetrated, whereas at 8 mg/mL, only 1 of 8 (13%) of oocytes was penetrated. The decrease in penetration was not associated with a decrease in sperm motility. In the second part of the study, sperm were incubated with the herbal solutions for 7 days. Both concentrations caused significant sperm DNA denaturation concomitant with decreases in sperm viability compared with controls. Extrapolation of these data to the reproductive risk of echinacea in males is difficult, in part because the concentration of echinacea in semen or sperm has not been studied (10). Moreover, although the doses used in this study are small fractions of the actual recommended human dose, there is no published evidence that the adverse effects observed have occurred in vivo.
BREASTFEEDING SUMMARY
No reports describing the use of echinacea during lactation have been located. For the reasons discussed above, and because of the immaturity of an infant’s metabolic and elimination systems, use of this herb should probably be avoided during nursing.
References
1.Blumenthal M, ed. Echinacea purpurea herb. In: The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin, TX: American Botanical Council, 1998:122–3.
2.PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company, 1998:816–23.
3.Natural Medicines Comprehensive Database. 3rd ed. Stockton, CA: Therapeutic Research Faculty, 2000:388–90.
4.Gallo M, Sarkar M, Au W, Pietrzak K, Comas B, Smith M, Jaeger TV, Einarson A, Koren G. Pregnancy outcome following gestational exposure to echinacea. A prospective controlled study. Arch Intern Med 2000;160:3141–3.
5.Echinacea. The Review of Natural Products. St. Louis, MO: Facts and Comparisons, 1996.
6.Pepping J. Alternative therapies: Echinacea. Am J Health-Syst Pharm 1999;56:121–2.
7.Zink T, Chaffin J. Herbal ‘health’ products: what family physicians need to know. Am Fam Physician 1998;58:1133–40.
8.Ernst E. Harmless herbs? A review of the recent literature. Am J Med 1998;104:170–8.
9.Miller LG. Herbal medicinals. Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998;158:2200–11.
10.Ondrizek RR, Chan PJ, Patton WC, King A. An alternative medicine study of herbal effects on the penetration of zona-free hamster oocytes and the integrity of sperm deoxyribonucleic acid. Fertil Steril 1999;71:517–22.