Certain nutrients occur at the same levels in premature milk as in term milk. Also, the overall calorie count is the same for both. Human milk contains lower levels of some nutrients than artificial formulas. Sometimes, lower nutrient levels are beneficial 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 to the amount in most artificial formulas. Because of the lower levels of these nutrients, the premature baby loses less water. Less water loss helps the premature baby maintain a stable body temperature.
The nutrient levels and the available calories are often adequate for "older" or "bigger" premature babies, and for many other high-risk babies. However, lower nutrient levels and the "full-term" calorie count in human milk may create problems for the low birthweight baby who weighed 3 pounds, 5 ounces (1,500 grams) or less at birth, or for babies with certain health conditions affecting digestion or the use of nutrients. These babies may not get enough of the minerals, such as calcium, phosphorous, and iron, from their mothers' milk alone. They also may need additional calories.
Although your milk is best, it may not always completely meet the nutritional needs of very small premature babies or some very sick newborns. Fortunately, adding to, or "fortifying," a mother's milk does not appear to diminish the nutritional and anti-infective benefits your baby will gain from receiving your milk. But it may help to better provide the nutrition your baby needs.
The most common ways of adding nutrients and calories include the following:
Hind milk feeding. When a higher calorie count is the only consideration, you may be asked to pump your milk for several minutes and then stop to change collection bottles. The early milk obtained while pumping is called fore milk and it is higher in other nutrients. The milk collected after the first several minutes is called hind milk and it tends to be higher in calorie-rich fats. Freeze any fore milk for later use if asked to provide hind milk for some feedings. Do not obtain only the hind milk for feedings, unless directed to do so by your baby's doctors and nurses.
Human milk fortifier (HMF). HMF contains several nutrients, especially certain minerals that are needed for proper bone development in low birthweight babies. HMF is added directly to a bottle of your own milk. Usually a powdered version is used when plenty of your own milk is available. Liquid HMF will be used if reduced amounts of your breast milk are available.
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 considered the best option, or when reduced amounts of your breast milk are available.
How long your baby receives added nutrients and calories will depend on your baby's age, weight, physical condition, and ability to effectively breastfeed.