Susan Carlson RD, CSP, LD, Beth Wojcik RD, LD, Anne Barker MS, RD, LD and Jonathan Klein MD - 08/11/11
Peer Review Status: Internally Peer Reviewed

Background

Human milk is the ideal feeding for all infants.  While the nutrient composition of human milk is ideal for term infants; protein and mineral content of human milk is insufficient to meet the needs of the growing preterm infant.  These deficits are particularly of concern in the smallest infants (ELBW < 1000 g and VLBW < 1500 g) who have the highest protein and mineral needs for growth.  While TPN will provide supplemental amino acids, protein intake may be limited if unfortified breast milk comprises > 50% of total fluid intake.  As the mineral content of TPN is limited, preterm infants will accrue a mineral deficit until fortification of human milk is initiated.  Fortification of Human Milk is indicated in order to supply the nutrients required and support the rapid rate of growth and bone mineralization in the preterm infant. 

Commercial human milk fortifiers are predominantly a protein and mineral supplement.  They also typically contain additional calories, electrolytes and vitamins. 

 

Nutrient requirements of preterm infants in comparison to intakes provided from unfortified and fortified human milk
Nutrients Nutrient
Requirements for preterm infants <1500 g
Unfortified
20 kcal/oz Breast milk*
24 kcal/oz
Br Milk + HMF*
27 kcal/oz
Br Milk + HMF*
30 kcal/oz
High protein
Br Milk + HMF*

Fluids
(ml/kg)

 

 

180

 

150

 

133

 

120

Energy (kcal/kg)

 

120

 

120

 

120

 

120

 

120

Protein
 (g/kg)

 

4

 

1.8

 

3

 

3.4

 

4.1

Calcium (mg/kg)

 

100-200

 

50

 

214

 

277

 

218

Phosphorus (mg/kg)

 

60 – 140

 

25

 

120

 

156

 

122

Sodium (mEq/kg)

 

3 – 5

 

1.4

 

2.2

 

2.4

 

2

Potassium (mEq/kg)

 

2 - 4

 

1.9

 

4

 

4.8

 

4.2

*Feeding Type
(Content based on use of powdered Similac HMF)

Studies have shown that the addition of human milk fortifier is associated with short-term improvements in weight, length, and head circumference growth.  Other studies suggest human milk fortifier may improve bone mineralization and neurologic outcome.  (1 – 5)

The addition of human milk fortifier is well tolerated.  An early study by Lucas et al showed an increase in infections (43% versus 31%) and NEC (5.8% versus 2.2%) in infants fed fortified versus unfortified human milk; however the infants in the study received > 50% of their feeds from formula (6).  Other studies with human milk fortifiers showed an increase in osmolality of the breast milk feeding after initiation of the supplement (7).  Recent changes in fortifier composition have minimized this effect by adding fat and reducing the carbohydrate content of the supplement.

The addition of human milk fortifier appears to have no effect on the IgA content of human milk or on the concentrations of natural killer cell subsets in preterm infants fed the fortified milk (8, 9).  While the addition of human milk fortifier has been found in some studies to temporarily delay gastric emptying and cause a short term increase in gastric residuals and emesis, fortification is not associated with an increase in number of held feedings, incidence of blood in stools, incidence in apnea and bradycardia, or a delay in advancement to full enteral feeds (5, 10 – 12).

Guidelines for the use of human milk fortifier

  1. Human Milk Fortifier (24 kcal/oz) is indicated for all breast milk fed infants weighing less than 2000 g.  Infants weighing 2000 – 2500 g may also benefit from the addition of HMF, particularly if they are SGA or demonstrated poor intake and/or growth.
  2. Human Milk Fortifier (24 kcal/oz) should be initiated when the infant is tolerating breast milk feeds of > 25 ml/day.  Infants receiving 25 ml of breast milk on the first day of feeds should wait until day of life 3 or 4 before starting HMF.
  3. Infants who have been tolerating breast milk + HMF feeds and are made NPO should be restarted on breast milk + HMF feeds.
  4. Indications for using concentrated breast milk feeds (27 kcal/oz or 30 kcal/oz high protein) in infants include:
    1. Fluid restriction < 140 ml/kg
    2. Poor weight gain (< 10 – 15 g/kg/d) on 120 kcal/kg of 24 kcal/oz Breast Milk + HMF
    3. Metabolic bone disease (alkaline phosphatase > 600 U/L) with poor bone mineralization on x-ray requiring increased intakes of calcium and phosphorus

Note: Infant must be tolerating full feeds with HMF (24 kcal/oz) prior to further advance in nutrient density

  1. Infants > 3000 g who require concentrated breast milk feeds should receive breast milk mixed with Term Formula Concentrate.
  2. Infants on breast milk concentrated with HMF (27 kcal/oz or 30 kcal/oz) who develop hypercalcemia (ionized calcium > 6.5 mg/dl) or hyperphosphatemia (phosphorus > 7.5 mg/dl) should receive a Nutrition Consult and be switched to the reduced mineral recipe to decrease mineral content (see specific recipe below).

Monitoring guidelines for infants on breast milk + HMF:

Preterm infants fed breast milk + HMF are at risk for hyponatremia due to the limited sodium content of these feeds and increased urinary sodium losses.  Infants fed concentrated breast milk feeds (> 27 kcal/oz) are at risk for hypercalcemia and hyperphosphatemia secondary to the increased mineral content of these feeds.

24 kcal/oz breast milk + HMF

  • Check electrolytes weekly until the electrolytes are stable (within normal limits) and the patient is no longer receiving IV fluids or oral electrolyte supplements.

27 kcal/oz breast milk + HMF

  • Check electrolytes weekly until the electrolytes are stable (within normal limits) and the patient is no longer receiving IV fluids or oral electrolyte supplements.
  • Check ionized calcium and phosphorus weekly while patient is on concentrated breast milk + HMF.  Contact NICU RD if ionized calcium is > 6.5 mg/dl or phosphorus is > 7.5 mg/dl for recommendations to reduce mineral intake with the use of term formula concentrate.

30 kcal/oz breast milk + HMF

  • Check electrolytes weekly until the electrolytes are stable (within normal limits) and the patient is no longer receiving IV fluids or oral electrolyte supplements.
  • Check ionized calcium and phosphorus weekly while the patient is on concentrated breast milk + HMF.  Contact NICU Dietician if ionized calcium is > 6.5 mg/dl or phosphorus is > 7.5 mg/dl for recommendations to reduce mineral intake with the use of term formula concentrate.

References:

  1. Faerk J, Petersen S, Peitersen B, Michaelsen KF.  Diet and bone mineral content at term in premature infants.  Pediatr Res. 2000 Jan;47(1):148-56.
  2. Gross SJ.  Bone mineralization in preterm infants fed human milk with and without mineral supplementation.  J Pediatr. 1987 Sep:111(3):450-8.
  3. Nicholl RM, Gamsu HR.  Changes in growth and metabolism in very low birthweight infants fed with fortified breast milk.  Acta Paediatr. 1999 Oct;88(10):1056-61.
  4. Pettifor JM, Rajah R, Venter A, Moodley GP, Opperman L, Cavaleros M, Ross FP.  Bone mineralization and mineral homeostasis in very low-birth-weight infants fed either human milk or fortified human milk.  J Pediatr Gastroenterol Nutr. 1989 Feb:8(2):217-24.
  5. Martins EC, Krebs VLJ.  Effects of the use of fortified raw maternal milk on very low birth weight infants. J Pediatr (Rio J). 2009;85(2):157-162.
  6. Lucas A, Fewtrell MS, Morley R, Lucas PJ, Baker BA, Lister G, Bishop NJ.  Randomized outcome trial of human milk fortification and developmental outcome in preterm infants.  Am J Clin Nutr. 1996 Aug;64(2):142-51.
  7. DeCurtis M, Candusso M, Pieltain C, Rigo J> Effect of fortification on the osmolality of human milk. Arch Dis Child Fetal neonatal Ed. 1999;81:F141-F143.
  8. Jocson MA, Mason EO, Schanler RJ.  The effects of nutrient fortification and varying storage conditions on host defense properties of human milk.  Pediatrics. 1997 Aug;100(2 Pt 1):240-3.
  9. Tarcan A, Gurakan B, Tiker F, Ozbek N.  Influence of feeding formula and breast milk fortifier on lymphocyte subsets in very low birth weight premature newborns.  Biol Neonate. 2004;86(1):22-8.  Epub 2004 Feb 20.
  10. Ewer AK, Yu VY.  Gastric emptying in pre-term infants:  the effect of breast milk fortifier.  Acta Paediatr. 1996 Sep;85(9):1112-5.
  11. McClure RJ, Newell SJ.  Effect of fortifying breast milk on gastric emptying.  Arch Dis Child Fetal Neonatal Ed. 1996 Jan;74(1):F60-2.
  12. Moody GJ, Schanler RJ, Lau C, Shulman RJ.  Feeding tolerance in premature infants fed fortified human milk.  J Pediatr Gastroenterol Nutr. 2000 Apr;30(4):408-12.

Recipes for fortified human milk - hospital use

breast milk + human milk fortifier for preterm infants

24 kcal/oz Breast Milk + HMF
      25 mL breast milk
      1 packet Human Milk Fortifier

27 kcal/oz Breast Milk + HMF
      100 mL breast milk
      6 packets Human Milk Fortifier

30 kcal/oz Breast Milk + HMF
      100 mL breast milk
      6 packets Human Milk Fortifier
      30 mL High ProteinTerm Formula Concentrate
(Note - Formula room will prepare high protein concentrate which is made by mixing 1 pkt beneprotein with 150 ml Term Formula Concentrate) 

Reduced calcium/phosphorus breast milk + HMF

27 kcal/oz Reduced Mineral Breast Milk + HMF
      100 mL breast milk
      5 packets Human Milk Fortifier
      20 mL Term Formula Concentrate

30 kcal/oz Reduced Mineral Breast Milk + HMF
      100 mL breast milk
      5 packets Human Milk Fortifier
      50 mL High ProteinTerm Formula Concentrate
(Note - Formula room will prepare high protein concentrate which is made by mixing 1 pkt beneprotein with 150 ml Term Formula Concentrate) 

Concentrated breast milk feeds for term infants

24 kcal/oz Breast Milk
      100 mL breast milk
      25 mL Term Formula Concentrate

27 kcal/oz Breast Milk
      100 mL Breast Milk
        50 mL Term Formula Concentrate

30 kcal/oz Breast Milk
      50 mL Breast Milk
      50 mL Term Formula Concentrate

Written:     5/31/05, Susan Carlson MMSc, RD, CSP, LD, Beth Wojcik RD, LD, and Jonathan Klein MD
Reviewed:     8/11/11; Susan Carlson MMSc, RD, CSP, LD, CNSC, Anne Barker MS, RD, LD and Jonathan Klein MD