Does Breast Milk Change When Your Baby Is Sick?

You may have heard that breastfeeding is one of the best ways to boost your baby’s immune system and prevent them from getting sick. That doesn’t mean that your baby won’t ever catch a virus. Babies tend to be little germ factories, whether they’re nursing or not.

If your nursing baby has caught a bug, you might be wondering in what way your milk will protect them. Does breast milk change in some way when your baby is sick? Should you continue nursing your little one when they’re sick? What about when you’re feeling unwell? (Hint: yes, yes, and yes!)

Even when your baby isn’t fighting a virus, your breast milk has a baseline of elements that help protect your baby from illnesses and infections. First, breast milk is full of antibodies. These antibodies are highest in colostrum, the milk your baby receives at birth and during the first few days afterward. The antibodies also continue to be present in your milk the WHOLE time you’re nursing your baby, even if you nurse well into toddlerhood or beyond.

Your milk also contains a blend of proteins, fats, sugars, and white blood cells that work to fight infections. Other immune-boosting elements include lactoferrin, lactadherin, antiproteases, and osteopontin — antivirals and anti-inflammatories that help keep your baby’s immune system strong.

According to the Academy of Breastfeeding Medicine (ABM), there is strong evidence, too, that breast milk changes when you’re sick. When a nursing parent is under the weather, antibodies against that infection begin to be produced immediately and are found in breast milk.

What about when it’s your baby who catches the bug first? ABM notes that disease-fighting elements start to increase in breast milk in this case as well. So the answer to “Does your breast milk change when your baby is sick” is, “Yes!”

More research needs to be done to get a fuller picture, but there is evidence that breast milk changes in response to a baby’s illness.

First, a study from 2012 found that when a baby has an active infection, the white blood cell content (macrophages) of their parent’s breast milk increases, as do other protective factors. This supports the idea that the immune defense provided by your nursing sick infants is active and responsive.

Next, a study in 2013 looked at what happened to the baseline amounts of leukocytes (a type of white blood cells) in breast milk during times of illness for the nursing parent or their nursed baby. The researchers found that leukocytes increased “significantly” when either the nursing parent or their baby was ill.

Once the illness passed, the level of leukocytes returned to normal baseline levels, suggesting a relationship between illness and leukocyte levels in breast milk. The study researchers concluded that there’s likely a strong association between the health of the nursing parent and infant and leukocyte levels of their breast milk.

You may have seen some viral social media posts depicting color changes in breast milk during times of illness. While these are certainly fascinating, there is no published evidence as of yet showing that these color changes are a direct result of breast milk changing in reaction to an infection from a nursed baby or nursing parent.

That doesn’t mean this isn’t possible — just that there’s no research to support it as of now. However, there is evidence that breast milk changes color for other reasons, including in reaction to something a nursing parent ate, a vitamin they took, or other external changes that may affect their milk’s color.

One example is this case report from 2012 of a nursing mother whose breast milk turned green as a result of a multivitamin she was taking. Breast milk is known to turn a rusty brown at times as a result of something called “rusty pipe” syndrome, which is where a little blood is found in milk during early breastfeeding, but soon resolves.

Other known causes of breast milk color changes include the fact that milk changes from the yellowish/gold color of colostrum when your baby is first born to the whitish color of mature milk. Even mature milk changes color throughout the day and from feed to feed. The more watery “foremilk” that comes at the beginning of a feed or when your breasts are very full has a more bluish hue. The fattier “hindmilk” that comes as your breasts empty usually appears more creamy and yellowish.

If you notice any changes in your milk that can’t easily be explained, you should reach out to a healthcare professional or lactation consultant for clarification.

These days, the illness parents of little ones are probably worried about most is COVID-19. Thankfully, there is research suggesting that it’s safe to breastfeed if you have COVID-19, and the World Health Organization (WHO) recommends that lactating parents with COVID-19 continue to nurse their infants.

There is even some research to suggest that nursing may protect babies against serious SARS-CoV-2 (the infection that causes COVID-19). An observational study found that babies who were nursed were less likely to test positive for COVID-19 than babies who didn’t receive any breast milk.

Additionally, antibodies for COVID-19 have been found in the breast milk of parents who have COVID-19 and parents who have been vaccinated against COVID-19. This means that a breastfed baby can likely have some immunity against COVID-19 even without getting sick or being vaccinated themselves.

Moreover, there’s no evidence that the SARS-CoV-2 virus itself can be passed to a baby via breast milk. In other words, if you have COVID-19, you can’t give it to your baby through your milk. All of these reasons are why experts urge parents to continue breastfeeding when either they or their babies are ill with COVID-19.

Breastfeeding has been found to prevent babies from getting sick in the first place, and protects against common childhood ailments such as ear infections, diarrhea and vomiting, pneumonia, and urinary tract infections. Even when your baby does get sick, breastfeeding has many benefits for your baby:

  • Breastfeeding has been found to lower the illness course and severity
  • Breastfeeding keeps your baby hydrated, and it’s often the one thing that babies can keep down when they’re vomiting or ill
  • Breastfeeding comforts babies, and keeps them close and bonded with their parents
  • Breastfeeding is good for parents too: it offers you a chance to sit and rest with your baby, and fills you with “feel good” hormones like prolactin and oxytocin that keep you emotionally balanced during stressful times, such as when your baby is sick

Researchers have just begun to scratch the surface of the ways that breast milk changes when your baby is sick. There is emerging evidence that breast milk increases its protections and immune-boosting properties when your baby is sick. What’s more, there is evidence that breast milk changes when a breastfeeding parent is sick.

Let’s not forget all the data out there showing the many protective elements found in breast milk, whether your baby is currently sick or not. The bottom line is that if your baby is sick, breast milk is one of the best ways to help them fight their illness.

If you have any questions about breastfeeding during times of illness, don’t hesitate to reach out to your healthcare professional.