Herbal Use During Breastfeeding

Herbal Galactagogues

One of the most common uses of herbals by nursing mothers is as a galactagogue. Innumerable plants are purported to be galactagogues and LactMed^® has records on 44 of the most common plants. Several excellent reviews on herbal galactagogues have been published, all of which conclude that insufficient scientifically valid evidence exists to claim that any are safe and effective.^2–5 Recall also that Academy of Breastfeeding Medicine policy appropriately recommends: “Medication should never replace evaluation and counseling on modifiable factors.” ⁶ This statement applies equally to herbals.

Although a placebo effect is probably a major contributor to galactagogue activity, one might be willing to accept lower levels of evidence, such as widespread and long-term use with a lack of serious adverse effects. The recent review of galactagogues from traditional Persian medicine in this journal reminds us that several herbals popular in the West have long histories of use in other cultures. ⁷ Asparagus racemosus (wild asparagus or shatavari) is used in India and is included in the official Ayurvedic pharmacopeia as a galactagogue. Coleus amboinicus, (torbangun), has been used as a galactagogue for hundreds of years in Indonesia with apparent safety.

Some herbal galactagogues have human or animal studies to support a possible mechanism. Barley, hops, and consequently beer contain a polysaccharide that increases serum prolactin. Several of the purported herbal galactagogues (e.g., fenugreek, wild asparagus, and black cohosh) contain phytoestrogens. Although potent estrogens inhibit lactation, these weak estrogens may compete with maternal estrogen at estrogen receptors to dampen its effect. Further exploration of estrogen partial agonists as galactagogues seems warranted. If a useful diagnostic method for determining the etiology of low milk supply were available, one could make more informed decisions about the most appropriate type of galactagogue to use. Instead, conventional medicines all target prolactin and herbal medicines target either prolactin, estrogen, or both using mixtures of herbs, and all without the benefit of knowing a specific cause.

Adverse Effects in Nursing Mothers

Many mothers feel that herbals are natural and, therefore safe, but adverse effects of herbals have been reported in nursing mothers. In fact, as with most drugs, mothers are more likely to experience adverse effects than their breastfed infants. A wide variety of adverse reactions have been reported with herbals, ranging in severity from mild to serious. ⁸ LactMed records provide information about potential adverse reactions in nursing mothers.

Toxic epidermal necrolysis occurred in a mother taking fenugreek as a galactagogue. Cross-reaction between fenugreek and chickpeas, peanuts, and other legumes in allergic patients is also possible. In high dosages, fenugreek can cause lowering of blood sugar, risking hypoglycemia in diabetic mothers, and interact with warfarin to cause bleeding.

Milk thistle is generally well tolerated with only mild side effects such as diarrhea, headache, and skin reactions. Rarely, severe allergies and anaphylaxis are reported. Cross-allergenicity is possible in patients allergic to members of the aster family, such as daisies, artichokes, common thistle, and kiwi. Milk thistle also induces cytochrome P450 2C9 and might lower blood levels of phenytoin and warfarin.

Diarrhea and hepatomegaly occurred in a woman taking malt beverages, fennel, fenugreek, and goat's rue as galactagogues. Oral or topical fennel can cause allergic reactions affecting the respiratory system or skin, including photosensitivity. Fennel should be avoided by mothers if they or their infants are allergic to carrots, celery, or other plants in the Apiaceae family because of possible cross-allergenicity. Likewise, because blessed thistle is a member of the ragweed family, allergy is a concern. Black cohosh reportedly can cause dizziness, nausea, headache, rash, and vomiting, and, rarely, hepatitis and allergic reactions have been reported. St. John's wort is a potent enzyme inducer and can lower the blood levels of a number of important drugs, such as certain immunosuppressants, oral contraceptives, and warfarin.

Adverse Effects in Breastfed Infants

Very few reports of side effects in breastfed infants from maternal use of herbal products exist. Whether this is because of their inherent safety, poor excretion of the active principles into breast milk, or a lack of publication of studies and case reports is not known, although a combination of all of these factors is likely. Manufacturers are required to report adverse effects that they receive to the FDA, but they are not usually published.

Some effects of plant materials on the breastfed infant are merely curiosities. For example, orange coloration of the skin occurred in the breastfed infant of a mother who ate 2 to 3 pounds or more of carrots weekly. ⁹ However, a few clear cases of infant toxicity have been reported. Two breastfed infants, aged 15 and 20 days, had lack of weight gain in the previous 7 to 10 days, as well as restlessness and vomiting during the previous day. Both of their mothers had been drinking more than 2 L daily of an herbal tea mixture containing licorice, fennel, anise, and goat's rue to stimulate lactation. After the mothers discontinued breastfeeding and the herbal tea, the infants improved within 24 to 36 hours. The authors attributed the infants' symptoms to anethole, which is found in both fennel and anise.

A study compared 33 women who reported that they had taken St. John's wort during breastfeeding to two control groups who were matched for either disease or age and parity. Mothers who were taking St. John's wort more frequently reported infant colic, drowsiness, and lethargy than mothers in the other groups.

A 9-day-old breastfed infant developed hemolytic anemia 48 hours after his mother began drinking tea made from Arnica flowers. The infant was otherwise healthy with normal glucose-6-phosphate dehydrogenase status. After exchange transfusions and phototherapy, the infant's anemia corrected and bilirubin decreased to 9.9 mg/dL. The mother stopped drinking the tea and resumed breastfeeding with no further hemolysis. Oral ingestion of Arnica products should be avoided because of its many toxic components.

In two studies, a total of 10 of 22 breastfed neonates appeared to have loose stools after administration of 65 mg of cascara as cascara fluid extract to their mothers. One herbal medicine expert recommends avoiding herbs that contain anthraquinone cathartics such as aloe and cascara, although senna pod preparations, such as Senokot, appear to be safe. He also recommends avoiding herbs containing unsaturated pyrrolizidine alkaloids, such as borage and comfrey. ¹⁰

A 17-day-old exclusively breastfed infant developed an urticarial rash on the chest, back, and upper extremities. The infant's mother had reportedly applied water boiled with stinging nettles to her breasts for cracked nipples. The infant's rash improved upon cessation of breastfeeding and did not recur when breastfeeding was resumed without maternal use of stinging nettle. Total IgE and specific IgE levels for stinging nettle were high in the mother and infant, and the infant had positive skin test for nettle at 2 months of age. Agents applied topically to the breasts can provide much greater drug dosages to the infant than agents taken orally by the mother.

Regulation of Herbal Quality

Just like the quality of fruit at the local market can differ from year to year and place to place, the quality and dose of active ingredients of herbal medicines can vary. In addition, cross-contamination has inadvertently occurred. Weeds can grow in your garden, and so can seeds of unwanted plants be brought to the field by the wind or birds and be harvested with the intended crop. Cross-contamination during processing can also occur. Cases of poisoning have been reported from herbal products contaminated with toxic herbals such as belladonna and digitalis. Herbal extraction and formulation methods may vary over time, resulting in products with variable amounts and proportions of ingredients. Crops grown in soil contaminated with heavy metals can result in high levels of lead and other toxic contaminants. In addition, some unscrupulous suppliers of herbal products intentionally add undeclared pharmaceuticals to their “herbal” remedies. Addition of sildenafil or similar drugs to herbal products for improving male sexual function, potent corticosteroids in anti-inflammatory products, and potent stimulants in weight loss products has been found. ⁸

One of the major limitations in reporting on dietary supplements is that the formulation and method of preparation of a product with a given trade name may change over time. Many commercially available dietary supplements contain combinations of ingredients, such as multiple herbs, vitamins, minerals, and omega-3 fatty acids. Trendy ingredients such as acai berry and pomegranate are often added and removed depending upon whether they are in vogue.

One method of dealing with quality issues is by setting standards for purity and content. This approach is taken by USP, which promulgates standards for herbal products, including the presence of the selected active ingredient(s) and tests for certain contaminants. ¹¹ Products that meet their standards can display a symbol on their label noting that it meets USP standards. Homeopathic drugs should meet standards in the Homeopathic Pharmacopoeia. ¹²

The FDA also compiles a list of ingredients that are called “generally recognized as safe” (GRAS) for inclusion into food and drug products. Many of these are plant products. ¹³ The GRAS list is based on the assumption that the ingredients will be taken in quantities similar to those found in foods, but herbal drug products can contain much greater amounts. For example, although fenugreek is on the GRAS list as a flavoring agent, this does not necessarily mean that large pharmacological doses are safe. Inclusion on the GRAS list does give some assurance that these herbals are not exceedingly toxic. LactMed denotes herbal products that are on the GRAS list: 35 of the 92 herbals currently listed in LactMed appear there.

Summary

Herbal medication use during breastfeeding has not been well studied, but a few cases of adverse reactions in breastfed infants have been reported. Herbals can adversely affect the nursing mother in several ways, including direct adverse effects and interaction with other maternal medications. Moreover, contamination with other herbals, potent drugs, and environmental contaminants can occur. Limiting use of herbs to those that have evidence of relative safety and herbal products that have been tested for purity can reduce the risks associated with herbal drug use.