Using botanicals during lactation requires careful consideration to prioritize infant safety. While herbs are often perceived as natural, many contain potent, concentrated compounds that act like pharmacological agents. The difference between adding a seasoning herb to a meal and consuming a concentrated herbal tea or supplement is substantial, dictating the potential effects on the mother and the breastfed infant. Because rigorous scientific study on most herbs during lactation is limited, a cautious approach is necessary when considering anything beyond typical culinary use.
How Herbal Compounds Transfer to Breast Milk
Once consumed, active chemical compounds from herbs enter the maternal bloodstream through the digestive tract and transfer into the breast milk. The physical and chemical characteristics of the compounds determine how readily this transfer occurs. Compounds with a smaller molecular weight (typically less than 300 Daltons) and high lipid solubility pass into breast milk more easily. Transfer is also influenced by the concentration in the mother’s blood, which relates directly to the dosage consumed. Only the unbound fraction of the compound circulating in the blood is available to diffuse into the milk compartment. In the first few days postpartum, the cellular junctions within the breast are slightly more open, potentially allowing a greater amount of various compounds to pass into the colostrum.
Herbs That May Decrease Milk Supply
Some herbs contain anti-galactagogue compounds that actively interfere with the body’s milk production process. These substances often impact the hormones involved in lactation, such as prolactin and oxytocin, or create a systemic “drying” effect. The key concern with these herbs is their medicinal concentration, not the small amounts used for flavoring food.
Specific Anti-Galactagogues
High doses of sage, especially when consumed as a concentrated tea or tincture, are frequently cited for significantly reducing milk volume. This effect is so pronounced that sage is sometimes deliberately used to suppress lactation. The menthol content in peppermint is also recognized for its potential to decrease milk supply. While a mild cup of peppermint tea is safe, consuming multiple strong cups daily or using concentrated peppermint oil products may reduce milk production. Excessive consumption of parsley, particularly in concentrated forms, is also believed to interfere with prolactin production. Lemon balm, related to the mint family, may also affect milk supply in a dose-dependent manner.
Herbs Posing Direct Safety Risks to the Infant
A separate category of herbs must be avoided entirely due to compounds that pose direct safety risks to the nursing infant. These adverse effects result from the toxicity or potent pharmacological action of the substances after they transfer into the milk. Kava-kava is strongly discouraged because of its association with potential liver damage and the risk of severe sedation in the infant. St. John’s Wort has been reported to cause symptoms like colic, drowsiness, and lethargy in breastfed babies. Herbs with strong laxative properties, such as high-dose Senna or Cascara sagrada, should be avoided, as active compounds can pass into breast milk and cause severe gastrointestinal distress, including diarrhea, in the infant. Large or long-term consumption of licorice root can also be problematic. The glycyrrhizin in licorice can lead to maternal hypertension and hormone disturbances, and excessive intake has been associated with signs of anethole toxicity in infants.
Seeking Expert Advice and Understanding Regulation
A primary challenge in assessing herbal safety is the lack of standardized regulation in the United States. Herbal supplements are classified as “dietary supplements” by the FDA, meaning they are not subject to the rigorous testing and pre-market approval required for pharmaceutical drugs. This regulatory difference results in significant variability in purity, potency, and ingredient concentration across different brands. Because of this inconsistency and limited scientific data, a mother should always disclose the use of any herbal supplement, tea, or essential oil to her healthcare provider or a knowledgeable expert. Consulting an International Board Certified Lactation Consultant (IBCLC) or a physician with expertise in herbal medicine provides guidance specific to the mother’s individual circumstances. Relying on professional advice ensures the decision is made with the best available information.