Feeding of the Newborn and Premature Infants DR. MAHMOUD MOHAMED OSMAN MBBCH, MSc (Pedia), MRCPCH (UK), FRCP (Edinburgh) Consultant Pediatrician & Neonatologist Al Yammamah Hospital, MOH

Specific nutritional requirements. Artificial feeding & formulas. Techniques of artificial feeding. Feeding the preterm infant. Total parenteral nutrition. OBJECTIVES:

I. Introduction: The ideal food for healthy full-term infants is breast milk. Premature infants have different nutritional requirements from full-term infants and need to be fed either directly into the bowel (Enteral feeding) or intravenously (Parenteral nutrition). Nutrition in early life has important implications for infants later life such as neurodevelopmental outcomes, obesity, hypertension, diabetes, and allergies.

II. Specific Nutritional Requirements: 1- Fluids: Water is the major constituent of infants, but its proportion varies with maturity. Newborn infants, especially preterm ones, have a higher percentage of total body water than children and adults. The daily requirement of the newborn is relatively higher than that of older children as his ability to conserve water is less. A healthy breastfed infant will consume as much fluid as is required, given ready access to the breast.

Healthy bottle-fed infants will also ‘know’ how much fluid they need and should be allowed to consume milk when they want it, to the volume that satisfies them. Many mothers feel that their baby should take all the milk at every feed, and overfeeding may become a problem. There are recommended feeding schedules to be maintained up to 3 months of age, and then reduced to 100 mL/kg/day up to the age of 1 year. Infants who have suffered intrauterine growth restriction should be fed to an expected weight as if they had grown normally in utero.

Total body water and extracellular fluid (Expressed as percentages of body weight)

Fluids in Preterm: Mechanisms for conserving water are poorly developed in immature infants, and their requirements depend on conceptual age, postnatal age and environment. Premature babies need to be given their requirements as they cannot take what they need. Ill preterm infants, may tolerate fluids poorly and develop worsening lung disease, PDA, and edema. Some very immature infants may lose large amounts of water through their kidneys or skin, and need significantly higher fluid intake.

Recommended feeding schedules (Fluid volume mL/kg according to day of life)

2. Energy and macronutrients: Energy requirements for optimal growth depend on the baby’s birth weight, gestational age and state of health. Ill babies are likely to be more catabolic and will have greater energy requirements. The smaller the infant the greater are the requirements per kilogram, and this is particularly so in intrauterine growth restriction infants (IUGR) . Of the recommended 120 kcal/kg per day of energy for the preterm infant, only 25 kcal/kg per day are for energy storage for growth.

Energy requirements for optimal growth At the end of the first week of life

A. Carbohydrate: The carbohydrate of human milk is lactose (90–95%) with small amounts of oligosaccharides (5–10%). Lactose (a disaccharide of Glucose and Galactose) must be metabolized to glucose for energy utilization in the brain and other organs. Approximately 40% of the infant’s total energy requirement comes from the carbohydrate

B. Fat: Fat in milk provides approximately 50% of the infant's energy requirements. Infants require 4–6 gm fat/kg/day. Human milk fat is better absorbed than cows’ milk fat. The mature infant absorbs about 90% of the fat in human milk, but preterm infants absorb only 75–80% of fat from human milk, and less from artificial milk. Unsaturated fatty acids are better absorbed than saturated fatty acids, and medium chain triglyceride better than long-chain triglyceride.

C. Protein Approximately 10% of the infant’s energy requirements is provided by protein. The recommended daily intake is 2.5 - 3.5 gm/kg per day for full-term infants and 3.0 –3.8 gm/kg per day for very premature infants. Milk protein is divided into curd (mainly casein) and whey (mainly lactalbumin). Human milk contains more whey, and cows’ milk considerably more curd. There are also important differences in the amino-acid profile of human and cows’ milk.

D. Minerals The recommended minimal mineral requirements for optimal nutrition are shown in the next table. In sick infants, particularly those receiving intravenous nutrition, it is important to monitor serum levels of these minerals and adjust intakes. Extra sodium may be required by the very-low birth weight (VLBW) infant, as there may be a high urinary loss for the first weeks of life. Potassium should not be given until adequate renal function has been established.

Recommended enteral intake of minerals (For term and VLBW infants)

E. Trace elements: Recommended enteral requirements of trace elements are shown the next table. Copper and zinc have been shown to be essential trace elements for newborn infants. Other trace elements thought to be essential are chromium, manganese, iodine, cobalt and selenium. Breast milk and modern formula feeds contain some of these elements.

Recommended daily enteral intake of some trace minerals

F. Iron Both preterm and term infants born to healthy mothers have sufficient iron stores at birth for 3 months in premature and 5 months in term infants. If the iron is not received in the diet, iron deficiency anemia will develop. Preterm infants should be monitored for iron deficiency anemia and supplemented with oral iron if needed. Some units routinely provide iron supplement without the need for blood tests.

G. Vitamins The fat soluble vitamins A, D, E and K are stored in . the body and large doses may result in toxicity. Excess doses of water-soluble vitamins are readily . . . excreted. The preterm infant requires more vitamin D (1000 IU/day). Vitamin K is the only vitamin in which the normal . . . . breastfed infant may become seriously deficient; . . . . . leading to haemorrhagic disease of the newborn. Vitamin K is given as intramuscular injection at birth. Routine vitamin E supplementation does not prevent . . late anemia, or chronic lung.

Recommended daily dosage for vitamin supplementation

III. Artificial feeding/formulas: If a mother fails to breastfeed or does not wish to undertake breastfeeding, she must not be made to feel inadequate or guilty. Successful bottle-feeding is much better than unsuccessful breastfeeding. Mothers make an informed decision not to breastfeed because of early return to work, adoption and previous lack of success.

1. Cows’ milk Unmodified cows’ milk is not recommended during the first 12 months of life because of: Its iron content is low and of poor bioavailability. It has higher levels of protein, sodium, potassium, phosphorus and calcium. It has a high renal solute load. It is lacking in vitamin C and essential fatty acids. There is potential gastrointestinal tract blood loss, secondary to cow’s milk colitis. Cows’ milk can be introduced into the infant’s diet during the second 6 months of life as custard, yoghurt and cheese.

2. Cows’ milk-based formulas: The manufacturers produce milks that are similar to mature breast milk in nutritional content; and are often marketed as ‘breast milk substitutes’ powders or ‘ready-to-feed’ liquids. . More recently, formula feeds have been developed that are better suited to the needs of premature infants. These modifications increase the cost of infant formulas. Casein dominant formulas are usually cheaper than whey-dominant ones.

3. Modificated formulas: 1. Starter and follow-on formulas: Starter formulas are suitable from birth to1 year. Follow-on formulas have slightly higher protein and electrolyte levels and are usually casein dominant. They are often recommended from 6 months of age.

2. Lactose-free cow’s milk-based formulas Lactose intolerance (LI) results from the deficiency of the enzyme lactase and may be primary (very rare) or secondary following gastroenteritis, malnutrition, protein allergy. Lactose-free cow’s milk-based formulas are usually the preferred choice for secondary LI, whereas more elemental formulas will be required for prolonged LI, especially if there is evidence of other malabsorption.

3. Preterm formulas Special formulas have been developed to meet the extra nutritional requirement of growing preterm infants. The protein content of preterm formulas (whey based) is higher than that of term formula (2.7–3 gm/100 kcal). They also have adequate levels of vitamins and minerals. Preterm babies should be discharged on these formulas, particularly babies with chronic lung disease or extreme preterms.

4. Soy formulas: There is no benefit over cow’s milk formulas as a supplement for the breastfed infant and no proven benefit in prevention of atopic disease. Soy-based formulas have low lactose content and are suitable for treatment of infants with Galactosaemia. Several of the soy formulas are both lactose- and sucrose-free and can be used for primary lactose or lactose and sucrose intolerance

4. Techniques of artificial feeding Volumes The daily required amounts should be given. Interval between feeds Term infants weighing less than 3 kg are initially fed 3-hourly. Infants over 3 kg can be fed on demand or 4-hourly. the night feed can be deleted if the infant does not wake. Sterilization A suitable technique for teats and bottles should be followed. Water used in the preparation of feeds must be bacteriologically safe. This may be conveniently achieved by boiling the water for 10 min before it is used. Preparation of feeds Guidelines suggested by milk manufacturers for their products should be carefully followed..

5. Feeding the preterm infant In utero the fetus grows at about 15 gm/kg/day and this is the goal for preterm infants of birth weight < 2kg, and ≥ 20 gm/day for infants > 2kg. Preterm infants have low body reserves of nutrients and high requirements because most nutrient accretion occurs in the last trimester. Specially adapted formula milks have been developed for the needs of premature babies that meet their nutritional requirements better than standard formulas. Some ill VLBW infants will not tolerate milk feeds and require parenteral nutrition.

6. Expressed breast milk Breast milk expressed from the mother who delivers preterm has many important properties that make it the milk of choice for the preterm infant. These include: Antiinfective properties reduce risk of infection. Possible reduced risk of NEC in premature infants. The presence of growth factors in milk. Advantages for cognitive development. Enhanced absorption, less steatorrhoea. Contains protein of high quality and bioavailability, plus unique fats and carbohydrates.

7. Trophic feeding Early exposure of the baby’s gut to enteral feeds, even if they are receiving parenteral feeding, has been shown to mature gut function. Low-volume hypocaloric feeds (2 mL/kg per hour) significantly reduce the time for a baby to reach full feeding compared with babies who do not have early feeding. This effect is probably mediated through the stimulation of gut hormones (priming the gut).

IV. TOTAL PARENTERAL NUTRITION Total parenteral nutrition (TPN) is not the preferred method for feeding infants and should be used only when appropriate enteral feeding is not possible. Supplemental parenteral nutrition is frequently practised while the preterm infant (< 30weeks’ gestation) slowly adapts to increasing enteral feeds. If TPN is going to be required, it should be introduced as early as the first day.

Indications The main indications for TPN are: Preterm infants < 30 weeks’ gestation or <1000 gm. Preterm infants >30 weeks but unlikely to receive full feeds by day 7. Severe IUGR. Necrotising enterocolitis (NEC). Gastrointestinal tract anomalies.

Methods of delivery The solutions used in TPN are highly irritant and may cause severe tissue damage if extravasation occurs. Administration of TPN through a long peripheral or central venous line is advisable. The TPN regimen aims to provide carbohydrate, fat, protein, electrolytes, minerals, vitamins and trace elements through standardized bags.. Lipid emulsion is given in separate syringe.

Enteral Parenteral Advantages Simpler Cheaper No CVC required Less monitoring Less complication Independent of GIT functions Disadvantages Dependent on GIT . functions Diarrhea Feed intolerance NG tube malposition Pulmonary aspiration Non physiological Requires venous access Higher risk of systemic infection Expensive More complication

IN SUMMARY Breast milk is the ideal food for normal babies, both term and preterm. The preterm infant fed unfortified human milk receives inadequate energy and nutrients to equal fetal accretion. Unmodified cow’s milk is not recommended during the first 12 months of life. The nutritional reference standard for the term newborn is the exclusively breastfed infant. TPN should only be used when enteral feeding is not possible or is going to be delayed.

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