Certain nutrients happen at the same levels in premature milk as in term milk. The total calorie count is also the same for both. Human milk has lower levels of some nutrients than infant formulas. Sometimes lower nutrient levels are good for premature babies. For instance, protein and sodium are at higher levels in premature milk than in mature milk. Yet they still are low when compared with the amount in most infant formulas. Because of the lower levels of these nutrients, the premature baby loses less water. Less water loss helps the premature baby keep a stable body temperature.
The nutrient levels and the available calories are often enough for "older" or "bigger" premature babies, and for many other high-risk babies. But lower nutrient levels and the "full-term" calorie count in human milk may cause problems for the low birth weight baby who weighed 3 pounds, 5 ounces (1,500 grams) or less at birth. They also cause problems for babies with certain health problems that affect digestion or the use of nutrients. These babies may not get enough of minerals such as calcium, phosphorous, and iron from their mothers' milk alone. They also may need more calories.
Your milk is best, but it may not always fully meet the nutritional needs of very small premature babies or some very sick newborns. Fortunately, adding to (fortifying) a mother's milk doesn't seem to lessen the nutritional and anti-infective benefits your baby will gain from getting your milk. But it may help to better give the nutrition your baby needs.
The most common ways of adding nutrients and calories are:
Hindmilk feeding. When a higher calorie count is the only need, you may be asked to pump your milk for several minutes and then stop to change collection bottles. The early milk you get while pumping is called foremilk. It's higher in other nutrients. The milk collected after the first several minutes is called hindmilk. This tends to be higher in calorie-rich fats. Freeze any foremilk for later use if asked to give hindmilk for some feedings. Don't get only the hindmilk for feedings, unless told to do so by your baby's healthcare provider.
Human milk fortifier (HMF). HMF has several nutrients. It especially has certain minerals that low-birth-weight babies need for proper bone development. HMF is added directly to a bottle of your own milk. Often a powdered version is used when you have plenty of your own milk. Liquid HMF will be used if you have reduced amounts of your breastmilk.
Premature infant formulas. Sometimes feedings of a mother's milk may be alternated with feedings of a premature infant formula. This may be done if HMF is not thought to be the best choice, or when you have reduced amounts of your breastmilk.
How long your baby gets added nutrients and calories will depend on your baby's age, weight, health, and how well he or she can breastfeed.