Herbs and Breastfeeding
Sheila I. Humphrey, BSc,
Dennis J. McKenna, PhD
from Breastfeeding Abstracts,
November 1997, Volume 17, Number 2, pp. 11-12.
Medicinal herbs can be defined as plants used to prevent or remedy illness. As our understanding of plant chemistry expands, drawing clear boundaries between food and herbs becomes increasingly difficult. Cultural attitudes toward herbs are currently undergoing rapid change, in part because new discoveries about old remedies are becoming known to scientists and the public. While much of the commonly encountered information about herbs does not meet scientific standards, a large body of research literature about medicinal plants does exist.1-8 However, scientific information about herb use during lactation, particularly recent studies, is comparatively sparse. 9-12
Nonprofit educational organizations, such as the American Botanical Council (ABC)27 and the Herb Research Foundation (HRF),28 maintain large collections of current scientific articles and books, as well as provide other resources such as Web sites and publications such as Herbalgram. Chemical and pharmacological data on thousands of plant constituents can also be found in textbooks, 3,4 on the Web, and through specialized computer databases, most notably Napralert, maintained by the Program for Collaborative Research in the Pharmaceutical Sciences at the University of Illinois at Chicago. While reliable predictions about safety during lactation cannot be made for all situations, pharmacological data can certainly help assess relative risk for the majority of herbs widely available for sale in the USA. Some recent texts1,2,6 and monographs13,14 focus on plants about which there is scientific evidence regarding efficacy and safety, and this information can help put the reader on firm ground.
Herbs differ from medications in that they frequently contain a large number of physiologically active constituents in very small amounts. It is logical to assume that each of these chemical constituents enter human milk following the same chemical principles that govern medications. Following the rule of thumb that approximately 1 percent of a chemical consumed by the mother will enter her milk,9 it is logical to conclude that overall extremely small amounts of any one plant constituent will be present in breast milk. This is not to say that adverse effects could not occur.
It is important to distinguish between safety issues in herbal medicine versus safety issues related to a particular herb. Side effects and toxic reactions to herbs are considered rare.15,16,17 Toxic effects of herbs are often not the fault of the herb itself, but are caused by products containing misidentified plants or contaminants such as bacteria, heavy metals, or even prescription drugs. Allergic reactions to herbs can occur, as with any other plant material. Problems associated with particular plants or product types are documented.2,5 Some plants are inherently dangerous, containing naturally occurring toxins, often with cytotoxic or carcinogenic effects. While the identities of the more common toxic plants are generally known, at least to plant chemists, older herbal texts may not reflect this knowledge.16
There have been occasional reports in the medical literature of adverse effects in infants from maternal use of herbs. Review of these cases has generally revealed either the use of misidentified plants, as in the infamous "hairy baby" story,18-21 or the inappropriate or mistaken use of dangerous herbs.22 Even though these cases were exceptional, involving non-medicinal plants or dangerous medicinal herbs, it should be kept in mind that some plant species have been or could be responsible for adverse reactions in the nursing child.
Some medicinal herbs contain phytochemicals that have strong effects on the body as part of their therapeutic action, i.e., purgatives.1 Highly purified or isolated extracts of plants, such as essential oils or other concentrated isolates may have markedly different effects on the body or may even be quite toxic compared to less refined extracts of the same herb.7, 23 A familiar example would be fennel oil compared to fennel tea. The German Commission E report considers fennel seed tea, when prepared using the dose guidelines given, to be useful for indigestion, whereas the internal use of fennel oil can cause serious neurological effects.2, 14 Similarly, the use of essential oils or other strong preparations on nipples where the child would directly ingest them is a potentially dangerous practice. Maternal use of strong-acting herbs or herbal preparations should also be considered a possible risk to the child during lactation, and milder alternatives sought. Dose-related toxicity is of particular concern with any potent herb. As with all medications, following the recommended dose guidelines included with all herb products would be a first line of defense against overdose.
Referenced herb textbooks can be very useful and sound sources of information about herbs. However, their authors are not necessarily knowledgeable about lactation, a fact that must be kept in mind in reading their recommendations for lactation, which are usually rather broad. Statements such as "avoid excessive intake" or "avoid using amounts greater than used as food" present vague dose guidelines, while the statement "avoid while breastfeeding" may seem unnecessarily constrictive. Choosing to err on the side of caution, some authors state that lactating women should not use herbs at all.1,6
Current thinking about the risks of chemical substances in human milk, whether they be medications, plant chemicals, or even chemical contaminants, takes into account the significant benefits of continued breastfeeding to the baby and the mother.24 In balancing the risks and benefits in a given situation, a medication is not considered absolutely contraindicated unless it is logical to assume harm, or evidence of harm has been documented.9, 25 The analysis of risk and benefits also takes into account the varied nature of lactation: newborns face different risks than older babies or toddlers because of immaturity; infants consume varying amounts of human milk; mothers may be looking forward to years of lactation yet need or desire the benefits of medicinals.25, 26 Although health care practitioners may wish otherwise, some mothers may refuse prescription drugs and insist on using herbal alternatives for a number of reasons. While these mothers may perceive herbs as "safer," there are both risks and benefits. As with medications mothers need knowledgeable individual assessment of their unique situation.
Current science-based writings on herbs may or may not mention the folkloric or traditional information available about the use of herbs as an aid to lactation. Ethnobotanical information stands separate from knowledge gained through application of the scientific method, but it may still be valid. While little research has been conducted on the use of herbs as lactation modulators, it would seem prudent to include these ethnobotanical considerations in any description of herb use. Practitioners working with breastfeeding women need to know that herbs such as sage, for example, may decrease milk supply, even though no lactation studies have been done to verify this. Despite an otherwise conservative stance on lactation, Newall et al.6 do not cite ethnobotanical information about using sage for weaning in their recommendations for lactation, although they describe sage's folkloric use as a treatment for galactorrhea in another section. Other texts likewise mention sage's reputation as a lactation suppressant, yet fail to highlight this information when considering use during lactation.2 Careful reading of all the information about an herb is required to glean lactation-related information. Reliance on a single text for information pertaining to lactation may be inadequate, all the more so if the ethnobotanical information has been ignored.
Future investigations of herbs in lactation are needed, and not just to clarify safety issues, although these concerns are paramount. Research into the current clinical uses of herbs as aids in breastfeeding difficulties is also needed, to put the practice on a rational basis. In addition, research into the relative risks and benefits of herbal versus medical therapies in such areas as postpartum depression and thrush would be beneficial. Investigations of traditional plant use have long been an important part of drug discovery and the study of human physiology. It is reasonable to expect that systemic interdisciplinary study of plants with lactation-modulating reputations would reveal new therapies and provide research tools for a deeper understanding of human lactation.
Sheila I. Humphrey is a La Leche League Leader who majored in botany in college. Her husband, Dennis McKenna, is an ethnopharmacologist in private practice, a Fellow of the Linnean Society, and an Advisory Member of the American Botanical Council.
- Tyler; V. E. Herbs of Choice: The Therapeutic Use of Phytomedicinals. Binghamton, New York: Pharmaceutical Products Press, 1994.
- Wichtl, M. Herbal Drugs and Phytopharmaceuticals: A Handbook for Practice on a Scientific Basis. English language edition ed. N. G. Bisset. Boca Raton, LA: RC Press, 1994. (This volume includes selected extracts from the German Commission E Monographs for Human Medicine, Section of Phytotherapy.)
- Duke, J. Handbook of Biologically Active Phytochemicals and Their Activities. Boca Raton, LA: CRC Press. 1992.
- Duke, J. Handbook of Phytochemical Constituents of GRAS Herbs and Other Economic Plants. Boca Raton, LA: CRC Press, 1992.
- Leung, A.Y and S. Foster. Encyclopedia of Common Natural Ingredients Used in Foods, Drugs, and Cosmetics. 2nd ed. New York: John Wiley & Sons, 1996.
- Newall, C.A., L.A. Anderson, and J.D. Phillipson. Herbal Medicines: A Guide for Health-Care Professionals. London: The Pharmaceutical Press, 1996.
- Tisserand, R., and T. Balacs. Essential Oil Safety. London: Churchill and Livingstone, 1995.
- McGuffin, M., C. Hobbs, R. Upton, and A. Goldberg, eds. Botanical Safety Handbook: Guidelines for the Safe Use and Labelling of Herbs in Commerce. Boca Raton, LA: CRC Press, 1997.
- Hale, T. Medications and Mother's Milk. Amarillo, TX: Pharmasoft Medical, 1997.
- Bingel. A.S. and N.R. Farnsworth. Higher plants as potential sources of galactagogues. Econ Med Plant Res 1991; 6:1-54.
- Roberts, K.A. Comparison of chilled cabbage leaves and chilled gelpacks in reducing breast engorgement. J Hum Lact 1995; 11(1): 17-20.
- Mennella, J.A. and G.K. Beauchamp. The effects of repeated exposure to garlic flavored milk on the nursling's behavior. Pediatr Res 1993; 34:805-8.
- American Herbal Pharmacopoeia and Therapeutic Compendium. St. John's wort: Quality control, analytical and therapeutic monograph. Herbalgram No.40, 1997.
- Farnsworth, N. R. Relative safety of herbal medicines. Herbalgram No.29, 36A-H, 1993.
- Shulman, A. Toxicological problems of traditional remedies and food supplements. Int J Alternative Complementary Med January 1997, pp.9-10.
- Yarnell, E. and L. Meserole. Toxic botanicals: Is the poison in the plant or its regulation? Alternative and Complementary Therapies February 1997, pp.14-19.
- Koren, G., S. Randor, S. Martin and D. Danneman. Maternal ginseng use associated with neonatal androgenization. JAMA 1990; 264: 2866.
- Awang, D.V.C. Maternal use of ginseng and neonatal androgenization. JAMA 1991; 265:1828.
- Waller, D.P., A.M. Martin, N.R. Farnsworth. and D.V.C. Awang. Lack of androgenicity of Siberian ginseng. JAMA 1992: 267:2329 (letter).
- Golightly, P. Herbal products and breastfeeding. ALCA News 7(1), April, 1996. Subsequently pub. in Keeping Abreast.
- Talalaj, S. and A. Czechowicz. Hazardous herbal remedies are still on the market. Med J Austr 1990; 153:302.
- Horowitz, R.S., K. Feldhaus et al. The clinical spectrum of jin bu huan toxicity. Arch Int Med 1996; 156:899-903.
- Newman, J. How breastfeeding protects newborns. Sci Am 1995; 273:76-79.
- Newman, J. When breastfeeding is not contraindicated. BREASTFEEDING ABSTRACTS 1997; 16(4):27-28.
- Lawrence, Ruth. Breastfeeding: A Guide for the Medical Professional. 4th ed. St. Louis: Mosby, 1994.
- American Botanical Council, P0 Box 201660, Austin, TX 78720, 512/331-8868. http://www.herbalgram.org
- Herb Research Foundation, Pearl St. #200, Boulder, CO 80302. 303/449-2265