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Supplying adequate nutrition to premature infants is an ongoing challenge. Common medical conditions that premature infants develop and therapies given to them can increase their nutritional requirements or interfere with the delivery of nutrients. This article outlines factors to consider when prescribing appropriate diet and nutritional supplements at hospital discharge.
L’alimentation satisfaisante des prématurés représente un défi constant. Les troubles médicaux communs que développent les prématurés et les traitements qui leur sont administrés peuvent accroître leurs besoins nutritionnels ou entraver la rétention des nutriments. Le présent article souligne des facteurs à envisager lorsque l’on prescrit le régime et les suppléments nutritionnels nécessaires au congé de l’hôpital.
Providing adequate nutrition for premature infants to support growth and neurodevelopment, and prevent nutrient deficiency diseases is an ongoing challenge. It is presumed that when premature infants reach full term gestational age and birthweight, their nutrient needs are the same as those recommended for healthy full term infants (1). However, the nutritional status of premature infants may be compromised because of common medical conditions and therapies that increase nutrient requirements or impede the delivery of adequate nutrition. Thus, each infant’s medical condition and nutritional status needs to be considered when prescribing the appropriate diet and nutrient supplements at hospital discharge.
In addition to meeting specific nutrient needs of sick premature infants, short term benefits have been reported in healthy premature infants who continue to consume commercial premature infant formulas or human milk supplemented with fortifiers after hospital discharge (2–7). The superior growth and bone mineralization of the infants fed enriched milk are thought to result from higher amounts of protein and minerals provided by these milks compared with term infant formulas or nonenriched human milk. Energy intake was similar among study groups. When infants are fed ad libitum, the major determinant of volume of milk intake is the energy density (2,8). Infants in the sutdy were, on average, 30 to 31 weeks’ gestational age, weighed 1100 g to 1200 g at birth and were 37 to 38 weeks’ gestational age at hospital discharge. Infants were fed enriched milks for periods ranging from eight weeks to nine months after hospital discharge. The study populations included appropriate weight for gestational age infants and small for gestational age infants, who may have different responses to dietary manipulations (9,10). However, the outcomes for the two groups of infants were not evaluated separately.
Whether these superior outcomes seen in early infancy influence long term outcomes remains unclear. Long term follow-up shows that premature infants have significantly lower bone mineral content at age four to 16 years compared with children born at term (11). If this lower bone mineral content is maintained into adulthood, affected individuals could have a significantly increased risk of developing osteoporosis. However, the long term effect of diet composition in infancy on later bone mineral content needs to be investigated further. Some studies have found improved head growth in those infants consuming enriched milk (2,3). Maintaining normal head growth, a crude indicator of central nervous system growth, is associated with superior neurodevelopmental outcomes of premature infants (10). Despite these observed short term benefits, the long term functional significance and potential adverse effects need to be evaluated before the consumption of enriched milks can be recommended for all premature infants after hospital discharge.
The nutrition goals in the postdischarge period include the provision of nutrients to meet recommended intakes (1) and any increased nutrient requirements, as well as the correction of nutrient deficiencies. Some common characteristics of infants at risk for nutrient deficiencies include very low birthweight (1), development of multiple or prolonged systemic illnesses that affect nutrient metabolism such as sepsis and bronchopulmonary dysplasia (12), the use of drugs such as steroids and diuretics (13,14), and prolonged use of parenteral nutrition (15). The nutritional status of these infants at hospital discharge determines their need for enriched milks and/or specific nutrient supplements in the postdischarge period.
Healthy premature infants who are exclusively or partially breastfed should continue taking iron and vitamins A and D supplements (1,16). Commercial iron fortified term infant formulas are appropriate for healthy premature infants who are formula fed. If infants are discharged before 38 weeks’ gestational age, they may benefit from the use of commercial iron fortified premature infant formulas or fortified breast milk, albeit less practical for breastfed infants, until they reach term gestational age. If an infant received enriched milk and/or nutrient supplements during their hospital stay, which were discontinued before discharge, he or she will need to be closely monitored for evidence of nutrient deficiencies.
Solid foods can be introduced to stimulate the development of oral motor skills when an infant is physiologically and developmentally ready at around four to six months corrected age (17). It is not uncommon for some premature infants to have a limited capacity for tolerating enteral feeds (fatigue, oxygen desaturation) (18). There is no urgent need to increase the intake of solid foods. In fact, it is more important to ensure that infants have an adequate intake of nutrient-dense milk.
After discharge from hospital, all premature infants need to be monitored for the development of the following:
Abnormalities that develop after hospital discharge need to be corrected using special foods, dietary supplements or special modes of delivery of nutrients, which are best provided with input of an experienced dietitian. Diligent monitoring of the infants is required to determine the duration of nutrition therapy.
Development of nutrient deficiencies is not uncommon among premature infants after hospital discharge. Early detection and intervention will not only prevent short term morbidity, but can potentially affect an individual’s health well into adulthood.
Reviewed by the Canadian Paediatric Society Board of Directors