Preterm breast milk and special formulas support infant growth. Full term breast milk is also well tolerated.
Preterm breast milk is well suited for the preterm infant. It contains higher concentrations of protein and its volume is low as preterm infants cannot feed on larger volumes. The composition of preterm breast milk resembles that of colostrum. Research has shown that it positively influences the intellectual growth of the infant. However preterm breast milk may be an inadequate source of calcium and phosphorus. So supplements of these nutrients are often added to the mothers expressed breast milk and fed to the infant from a bottle.
Skillful monitoring of the nutritional status and care must be given to the premature infant. Optimal nutrition that corrects deficiencies and promotes growth should be given.
Nutrient needs and feeding methods will vary as the infant matures.
Without a full gestation, preterm infants face life threatening problems. Early intervention can enhance their survival and long term physical growth and mental development.
Infants of gestational age > 34 weeks are usually able to coordinate sucking, swallowing, and breathing, and so establish breast or bottle feeding. In less mature infants, oral feeding may not be safe or possible because of neurological immaturity or respiratory compromise. In these infants milk can be given as a continuous infusion or as an intermittent bolus through a fine feeding catheter passed via the nose or the mouth to the stomach.
Infants can be fed using a gastric tube if they are unable to breast or bottle feed
A major concern with the introduction of enteral feeds (especially to very preterm, growth restricted, or sick infants) is that the additional physiological strain on the immature gastrointestinal tract may predispose to the development of necrotising enterocolitis. The risk of necrotising enterocolitis is inversely related to gestational age and birth weight. The incidence is 5-10% in very low birth weight infants. The mortality rate is reported consistently as greater than 20%. Long term morbidity may include substantial neurodevelopmental problems, the consequence of undernutrition and associated infection during a vulnerable period of growth and development.
Human breast milk is the recommended form of enteral nutrition for preterm infants. The milk could be from the infant's mother or expressed milk from donor mothers, who are usually mothers who have delivered term infants. The nutrient content of expressed breast milk varies depending on the stage of lactation at which it is collected. Milk expressed from a donor's lactating breast has a higher calorie and protein content than that collected from the opposite breast (drip breast milk).
Despite optimal maternal support, expressed breast milk may not always be available. As an alternative, preterm infants may be fed with a variety of artificial formula milks, mainly modified cow's milk. Broadly, these may be “term” formulae (based on the composition of mature breast milk), or calorie, protein, and mineral enriched “preterm” formulae (tailored to support intrauterine nutrient accretion rates). Some evidence exists that feeding every preterm infants with preterm formula milk increases the rate of weight gain and head growth, at least in the short term, and improves some neurodevelopmental outcomes. No evidence exists that feeding preterm infants with formula milk supplemented with long chain polyunsaturated fatty acids is beneficial.