The question of whether to continue nursing while ill is common, but the answer in nearly all cases is a reassuring yes. Health authorities widely recommend continuing to breastfeed when a mother has a common illness because the benefits to the infant far outweigh any minimal risk. A mother’s body produces specialized defenses against the sickness, which are then transferred directly to the baby. When a parent falls ill, the protection offered by breast milk becomes even more immediate and beneficial.
How Breast Milk Protects the Infant
Breast milk is dynamic, constantly adjusting in real-time to meet the baby’s changing needs and combat environmental threats. When a parent is exposed to a pathogen, their immune system immediately produces specific antibodies that are passed into the milk supply. This process is a highly effective form of passive immunity, providing the baby with targeted defenses against the specific illness the mother is fighting.
The primary antibody transferred through milk is secretory immunoglobulin A (sIgA), which coats the mucosal linings of the baby’s throat, lungs, and intestines. Unlike other antibodies, sIgA is not absorbed into the infant’s bloodstream but forms a protective barrier on these surfaces, blocking germs from attaching and causing infection. This mechanism is important because the baby is often exposed to the infectious agent before the parent shows symptoms, making the milk an immediate source of protection.
Other immune components also contribute to the milk’s protective power, including lactoferrin, white blood cells, and oligosaccharides. Lactoferrin binds to iron, which some bacteria need to grow, effectively starving the pathogens. Most common infectious agents, such as those causing colds or flu, are not transmitted through the breast milk itself, making continued nursing safe.
Specific Guidance for Common Parental Illnesses
For most respiratory infections, including the common cold, influenza (flu), and COVID-19, the recommendation is to continue breastfeeding while implementing strict hygiene practices. These illnesses are spread through respiratory droplets, not via the milk supply. The primary risk to the infant comes from close contact during feeding, which is managed by simple measures.
Before handling the baby or any pumping equipment, the mother should wash her hands thoroughly with soap and water or use an alcohol-based hand sanitizer. Wearing a well-fitting face mask during direct nursing minimizes the transmission of virus-containing droplets. If a mother is too unwell to hold the baby for direct nursing, expressing milk is the recommended alternative.
Expressed milk can be fed to the baby by a healthy caregiver, maintaining the infant’s protective antibody intake while limiting direct contact with the sick parent. All pump parts and feeding items must be cleaned and sanitized after each use to prevent surface transmission. Continuing to nurse also ensures the mother’s milk supply is maintained, preventing the need for formula feeding when the baby needs the immune factors most.
Situations Where Breastfeeding May Need to Stop
While continued nursing is encouraged, there are specific situations where breastfeeding may be temporarily or permanently contraindicated for the baby’s safety. Conditions known to transmit through breast milk or pose a serious health threat fall into this category. One example is the rare metabolic disorder classic galactosemia, as affected infants cannot process a sugar found in milk.
In high-income countries like the United States, mothers who are HIV-positive are advised not to breastfeed, as the virus can be transmitted through milk, even with modern antiretroviral therapy. Other contraindications include the human T-cell lymphotropic virus (HTLV-I/II) and specific cancer treatments, such as chemotherapy drugs that interfere with cell division and can harm the infant.
Temporary cessation is required for conditions like active, untreated tuberculosis (TB), which is highly contagious through the air. In this case, the mother should be isolated from the baby, but can pump and discard her milk to maintain supply until she has been on treatment for about two weeks and is cleared as non-contagious. Similarly, the use of diagnostic radioactive substances may require a temporary pause in nursing, with the duration depending on the specific substance used.
Managing Medication Intake
When a mother is ill, she may need medication, which introduces a separate safety concern. Most medications are safe to use while breastfeeding, but it is necessary to consult a healthcare provider or pharmacist. Safety is determined by the “relative infant dose” (RID), which is the calculated amount of the drug the infant receives through milk compared to the weight-adjusted dose the mother is taking.
A relative infant dose of less than 10% is considered safe and clinically insignificant for the baby. Resources like the LactMed database, maintained by the U.S. National Library of Medicine, provide evidence-based information on the transfer rates and potential effects of thousands of drugs. Safe categories include most non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, and acetaminophen for pain and fever.
Medications that require more caution include certain decongestants, such as pseudoephedrine, which may decrease milk supply or cause irritability in the infant. Some psychiatric medications and opioids also need careful monitoring and dosing adjustments. Mothers should inform their prescribing doctor and pharmacist that they are nursing so they can select a drug with a low transfer rate, a short half-life, and the lowest effective dose.