Nutritional needs of preterm babies

There are different types of food for a preterm baby in the neonatal intensive care unit (NICU):

  • Mother’s milk
  • Donor milk from a human milk bank
  • Formula 
  • Combination of mother’s/donor milk and formula

Several studies have shown that mother’s milk is the best form of nutrition for term and preterm born infants. If mothers cannot provide enough breast milk, it can be supplemented with donor milk from an established human milk bank that follows specific safety regulations or a preterm infant formula.

Even though early preterm milk has a higher protein content, it is still not sufficient for the high needs of many of these infants and normally needs to be fortified with additional nutrients, in particular protein, calcium and phosphorus, to meet the baby’s increased needs. It is well tolerated and digested in preterm babies and results in faster weight gain.

Breast milk for preterm babies

Preterm infants have higher nutrient requirements than term infants. One reason for this is that they miss the third trimester of pregnancy which is the intended period of nutrient accumulation and rapid growth. During this time period the foetus swallows around 750 ml of amniotic fluid every day supporting the development of the digestive tract. The digestive tract of preterm babies is immature and functions such as intestinal movements, secretion of protective digestive substances and the digestion and absorption of food are reduced. Human milk is the most suitable food for these babies because it contains many protective enzymes, hormones and growth factors that play important roles in gastrointestinal development and maturation.

Depending on gestational age, preterm infants may benefit less from the transfer of antibodies across the placenta during the last period of pregnancy. However, they can still receive antibodies through feeding with mother’s milk. The immunologic aspects are especially relevant for preterm infants who are at a higher risk for infections. Additionally to all positive effects of breast milk for newborns, studies report reduced risk of respiratory infections (e.g. lung inflammation), sepsis (blood poisoning), and necrotizing enterocolitis (NEC) (disease of the intestinal tract, caused by inflammation or decreased blood supply to the bowel) in breastfed preterm babies.

Nutritional supplements

As preterm babies were not able to get the necessary time to develop and grow in the womb of their mothers, they may need nutritional supplements in addition to breast milk for a limited time.Brain, lungs and kidneys are still developing and therefore need adequate nutrition. Extra protein will be added to sufficiently support the development of the brain and to achieve the best growth in length and weight. The growing bones also require minerals like calcium and phosphorus. These supplements are especially important for preterm infants because they missed the normal period of accumulation of these minerals in the third trimester of pregnancy.

These extra nutrients will be added to the milk before it is fed to the baby, e.g., through a feeding tube (small tube to provide nutrition to neonates, who are not able to suck and swallow on their own). They can be added individually to the milk or can be provided by using commercially available liquid or powdered fortifiers which combine several extra nutrients to enrich breast milk.

Nutritional needs of the baby are assessed by healthcare professionals at the neonatal intensive care unit (NICU) and they decide together with parents what is best for the individual preterm infant.In some cases, it may not be possible to provide a sufficient amount of breast milk. In these cases, special formulas for preterm infants are available. These special formulas contain higher energy, proteins and minerals than formula for babies born at term in order to meet their growth requirements.