How is a preterm mother's milk different?

The milk of mothers who give birth prematurely (preterm) is somewhat different than milk made by women after a full-term baby's birth. It's different in the following ways.

Important nutrients

Studies have found more fat, protein, and the minerals sodium, chloride, and iron in "preterm milk" than in "term" milk. It is uniquely suited to meet a preterm baby's needs.

Premature babies who get breastmilk tend to develop better eyesight. They and other high-risk babies fed breastmilk often do better on intelligence tests as they grow older. This is mostly because of certain types of fats (fatty acid chains) in breastmilk. Infant formulas can't supply these same fats in the same amounts. Yet these fats are important for the growth and development of a high-risk baby's eyes, brain, and nervous system.

During the last weeks of pregnancy, a baby builds a lot of body tissue. Because preemies are born early, they must build this tissue after birth. Protein is needed to build it. Preterm milk has a bit more protein. Also the protein is in a form that is more easily used by your baby. Other extra proteins in preterm milk have higher levels of certain anti-infective properties. This includes some that protect babies against digestive and respiratory infections.

Fights infection

Only breastmilk is alive with many kinds of disease-fighting factors that help prevent mild to severe infections in babies. Preterm milk has higher levels of these factors. Antibodies in breastmilk directly protect against infection. Other factors in the milk make an environment that is friendly to "good" bacteria (normal flora). These factors are also not friendly to "bad" bacteria, viruses, or parasites. Breastmilk also seems to have factors that help a baby's own immune system develop and work best.

The disease-fighting factors in breastmilk are especially good for premature and other high-risk babies. This is because these babies are more likely to pick up infections more easily. Babies getting breastmilk are many times less likely to have diarrhea. They are also much less likely to get a serious digestive illness called necrotizing enterocolitis while in the neonatal intensive care unit. If any of these problems do happen, they are often less severe for the baby getting breastmilk. Babies who are fully or almost-fully breastfed and those getting expressed breastmilk also have fewer GI, respiratory, ear, and urinary infections after leaving the hospital.

Easily digested

Because nature made breastmilk for babies, your milk is the most easily digested food your baby can get. A nutritious and easily digested first food is important for any baby. But it is particularly good for the immature digestive tract of a premature baby and the more sensitive systems of many other high-risk babies. Your baby is able to break your milk down more fully into its basic parts. And it takes less energy than it would take to digest formula. So the nutrients, infection-fighting factors, and all of the other "ingredients" in your milk are more available to fuel your baby's body and to help growth and development.

Easily used

Bioavailability refers to how well the body can use the nutrients in a food. Breastmilk has high bioavailability. This means your baby gets more benefits from those nutrients. This is true even for nutrients such as iron that are at lower levels in breastmilk when compared with infant formula. Your baby's body can soak up these nutrients and use them. It also means your baby saves the energy that would be needed to get rid of any nutrients they had a hard time digesting or using.

Just right

Your milk is just right for your baby's body systems. This suitability lets your baby digest and use the milk easily and spend much less energy on body functions. Suitability is also thought to be a reason that babies getting breastmilk are less likely to develop allergic-related skin problems.

All of these benefits of breastmilk mean your baby's body is able to work less yet get more nourishment. This means less stress for the baby's heart, lungs, bowels, and kidneys. It also lets your high-risk baby use more energy to grow and get better. By giving your baby breastmilk, you are creating a medicine that no hospital can make. Babies who get this medicine are often ready for oral feedings earlier. They can also go home sooner than high-risk babies getting other types of feedings.