When a breastfeeding mother develops a cold, the need for symptom relief conflicts with the desire to protect the nursing infant. The common cold, which primarily causes symptoms like a runny nose, is typically a self-limiting viral infection. Seeking relief often involves over-the-counter medications that carry the potential for transfer into breast milk. Making safe therapeutic choices requires understanding both the mechanism of drug transfer and the specific properties of common cold medications.
How Medications Enter Breast Milk
Most drugs present in the mother’s bloodstream will transfer into her breast milk. This transfer is governed by the drug molecule’s physical and chemical characteristics. Smaller drug molecules, generally those with a molecular weight under 300 Daltons, pass more easily into the milk compartment.
A drug’s ability to dissolve in fats, known as lipid solubility, is another major determinant, as the cellular membranes lining the milk ducts are lipid-based. Highly lipid-soluble medications cross these membranes more readily, leading to higher concentrations in the milk. Conversely, drugs that bind extensively to proteins in the mother’s blood plasma are less available to diffuse. Only the unbound, or “free,” fraction of the drug can readily transfer.
Over-the-Counter Options Generally Considered Safe
Saline and Antihistamines
For a runny nose, the first line of defense involves saline nasal sprays and rinses. These products use a sterile saltwater solution to moisturize the nasal passages and thin mucus, providing localized relief without systemic absorption into the bloodstream or breast milk. They can be used as frequently as needed and have no effect on milk production. When allergy symptoms contribute, non-sedating antihistamines are preferred during lactation. Medications like loratadine (Claritin) and cetirizine (Zyrtec) transfer into breast milk in minimal amounts. Studies show the relative infant dose for these second-generation antihistamines is very low, posing little risk of sedation or other side effects for the nursing baby.
Decongestants and Milk Supply
Oral decongestants, such as pseudoephedrine, offer effective relief but must be used with caution due to their impact on milk volume. While only small amounts are secreted into breast milk, the drug is known to reduce milk supply. One study showed that a single 60 mg dose of pseudoephedrine reduced milk production by approximately 24% over 24 hours. For congestion relief without this systemic risk, localized nasal decongestant sprays are a better alternative. Sprays containing ingredients like oxymetazoline or xylometazoline act directly on the nasal tissues and are minimally absorbed. These should only be used for a few days to avoid rebound congestion, where the congestion returns worse after the medication is stopped.
Non-Pharmacological Strategies for Relief
Non-drug remedies offer effective relief for mild to moderate runny nose symptoms while entirely circumventing the concern of drug transfer to the infant.
- Maintaining proper hydration is effective, as drinking plenty of clear fluids helps to thin nasal secretions. Warm liquids, such as broth or decaffeinated tea, can be particularly soothing.
- Using steam loosens mucus and soothes irritated nasal membranes. This can be achieved by taking a hot shower or sitting in a steamy bathroom for several minutes.
- A cool-mist humidifier running, especially at night, adds moisture to the air, which helps prevent the nasal passages from drying out.
- Nasal irrigation devices, such as Neti pots or bulb syringes, use a saline solution to flush out mucus and irritants. This mechanical cleansing poses no risk to the nursing baby or milk supply.
- Adequate rest is also important, as the body requires energy to fight a viral infection.
Medications to Avoid and Potential Risks
Sedating Antihistamines
Certain over-the-counter cold medicines are best avoided during breastfeeding due to potential risks to the infant or to the mother’s lactation success. Older, first-generation antihistamines like diphenhydramine (Benadryl) should be used with extreme caution. These medications are sedating, and their transfer into milk can cause drowsiness, irritability, or poor feeding in the infant. They also carry a higher risk of negatively affecting the mother’s milk supply, especially with prolonged use.
Phenylephrine and Combination Products
The decongestant phenylephrine, often found in oral cold remedies, is another ingredient to treat with reserve. This drug has very low oral absorption, which means little reaches the bloodstream, but there is limited data on its safety during lactation. Furthermore, the Food and Drug Administration (FDA) recently concluded that oral phenylephrine is not effective as a decongestant. Multi-symptom cold products should also be approached with skepticism. They often contain a combination of ingredients, some of which may be unnecessary or risky for a nursing mother. These combination medications can include alcohol, which is a hazard to the baby, or multiple active drugs that increase the infant’s overall exposure. It is always safer to choose single-ingredient products that target only the specific symptoms being experienced.
Risk of Milk Suppression
The most significant pharmacological risk for a breastfeeding mother is the suppression of milk production, which is a common side effect of many drying agents used for a runny nose. Both pseudoephedrine and sedating antihistamines reduce secretions throughout the body, and this drying effect extends to the mammary glands, potentially decreasing the volume of milk produced. Any mother considering medication should speak with a healthcare provider or lactation consultant to weigh the benefits of symptom relief against the risk of reduced milk supply.