Possible implications of teratogenic or mutagenic effects are often suggested on the basis of in vitro and animal data. Although such data are certainly useful, they cannot be used to predict reproductive effects in humans because the teratogenic potential of a substance may vary considerably among species.
To date, in vitro studies of bacterial and mammalian cells as well as in vivo studies of mice have found no evidence of mutagenicity associated with Echinacea (Mengs et al., 1991). There are no human studies pertaining to the effect of Echinacea on female fertility at this time. Recent in vitro studies, however, suggest possible impaired male fertility associated with Echinacea use (Ondrizek et al., 1999a, 1999b). This research found that high concentrations of Echinacea added directly to semen decreased sperm movement. But it is not always possible to extrapolate results stemming from in vitro research to humans, especially in light of the high concentrations used.
There are many implications for healthcare practitioners given the growing popularity of herbal therapy, combined with the lack of awareness for potential risks associated with unregulated products. Due to the lack of evidence-based data, health professionals caring for pregnant women are often confronted with the difficult task of counseling on the risks versus benefits of using Echinacea during pregnancy (Lepik, 1997). A recent study compared the attitudes and practices of physicians and naturopaths with respect to herbal products in pregnancy (Einarson et al., 2000). All naturopaths surveyed asked patients about both conventional and complementary therapy use. On the contrary, only 56% of physicians surveyed asked patients about complementary therapies during routine history taking. Despite the paucity of information for herbal use during pregnancy, naturopaths are more inclined to recommend herbal products in pregnancy. However, most pregnant women are generally under the care of conventional physicians. Lack of clinical evidence concerning safety in pregnancy was reported by these physicians to be the main reason for their hesitation, not because they deem them unsafe.
In an attempt to close this gap, the Motherisk Program conducted and published the first prospective controlled study on Echinacea use in pregnancy (Gallo et al., 2000). The Motherisk Program is a teratogen information and counseling service that provides evidence-based data to pregnant and nursing women and their healthcare professionals on the safety/risk of exposures such as drugs, chemicals, radiation, and infectious diseases. In service since 1985, questions posed to the program over the years have mirrored changing trends in the general population. The popularity of herbal products is reflected in the visible increase in the number of inquiries regarding the effect of these remedies in pregnancy and lactation. In the past 3 years, the total number of calls to the program averaged 32,000, with approximately 5% of all calls related to herbal products, translating to more than 1,600 calls per year.
The overwhelming number of inquiries in combination with the paucity of data prompted the need to address the implications of Echinacea in pregnancy. While the primary objective of the study was to determine pregnancy outcome associated with Echinacea use, secondary endpoints looked at pattern of use. The study consisted of women who initially contacted the Motherisk Program regarding the safety of consuming Echinacea in pregnancy. The study cohort included 206 women exposed to this herb who were disease matched to a control group of 206 women who had subsequently decided not to use it. Results indicated that gestational use of Echinacea is not associated with an increased risk for malformations above the baseline risk. In addition, no significant differences were reported in pregnancy outcome, delivery method, or fetal distress. Capsules, tablets, and tinctures were the most popular of several formulations of Echinacea angustifolia and Echinacea purpurea species used by participants. About 81% of women reported Echinacea to be effective in improving their upper respiratory tract symptoms. Moreover, 95% rated their perception of risk for gestational use of this herb as low. This was a reflection of the general population's perception that because herbal products are natural, they are safe.
It is well documented that consumption of herbal medicine can result in direct adverse effects, such as allergic reactions, nausea, vomiting, and sedation (Ernst and De Smet, 1996). Most medicinal plants contain scores of active ingredients, and unlike conventional medicinal drugs, concentrations of these elements differ from one crop to the next and even within the plant itself. As with any unregulated products, Echinacea use during pregnancy and lactation can be of concern, especially with issues of dosage variation, contamination, incorrect labeling, and interactions with other medications (Smith et al., 1996). For this reason, it is essential for pregnant and nursing mothers to be educated about these issues.
There is much controversy surrounding the issue as to whether Echinacea can be used for extended periods of time. The German Commission E does not recommend continuous use of Echinacea beyond 8 weeks (Blumenthal et al., 2000). Theoretical concerns of hepatotoxic effects associated with long-term Echinacea use have been suggested, but never substantiated (Miller, 1998). Unknown implications of prolonged use prompted most women in the Echinacea study to limit use to a few days, as this was reportedly sufficient in alleviating the initial symptoms of a cold. Only two women reported use on a daily basis to maintain their immune system, with no resulting adverse pregnancy outcome (Gallo et al., 2000).
It is critical to check labels as various other products can be found in combination with Echinacea. For example, goldenseal is contraindicated in pregnancy. While Echinacea may be safe, goldenseal, which is often contained in Echinacea products, contains pharmacologically active alkaloids that can lead to uterine-stimulating effects (Farnsworth et al., 1975). Consequently, potential harm could be introduced to an unsuspecting pregnant woman. An added concern in purchasing Echinacea is the practice of substitution. Potential for product impurity and contamination through adulteration can lead to numerous complications in pregnancy.
Consumption of large amounts of alcohol-containing Echinacea tincture has been linked to possible theoretical risks for alcohol-related effects in the developing fetus. However, the pattern of use for Echinacea products is commonly on an intermittent and infrequent basis during pregnancy. The alcohol content found in the tincture form, when taken at maximal recommended dosage, will approximate to 1 to 2 mL (~1 tsp daily) (Newall et al., 1996). Given that pregnant women tend to use much lower dosage for shorter periods than generally recommended, this minimal amount of alcohol is highly unlikely to have an effect on pregnancy outcome (Gallo et al., 2000).
The potential for herbal remedies to interact with conventional pharmacotherapy exists, as many women do not reveal their use of herbs to their physicians (Miller, 1998; Von Gruenigen et al., 2001). This may present significant concerns since many pregnant women consume Echinacea supplements concurrently with over-the-counter and prescription cold medications (Eisenberg et al., 1998).
There is currently no information regarding the transfer of Echinacea into human milk or its impact on the nursing infant (O'Hara et al., 1998). This herb generally consists of nontoxic components and hence, little or no toxicity is expected when taken at recommended doses (Hale, 2000). It is important to obtain Echinacea from a reliable source, as use of adulterated products can lead to the possibility of exposing the infant to hidden contaminants that can excrete into the breast milk (Kopec, 1999).
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