This clinical guideline discusses nutritional requirements for preterm infants receiving enteral nutrition. It does not give guidance on the prescription of parenteral nutrition.
Definitions
Nutritional requirements
Preterm infants have higher nutrient requirements than term infants (
Tsang et al 2006) (
Rationale 1).
Energy requirements for preterm infants are estimated to be around 110-150kcal/kg/day (
American Academy of Pediatrics 2004). See
Appendix 1 for summary of preterm requirements.
These recommendations for requirements are for infants <1500g birth weight, although most infants born <2000g will benefit from these nutrient recommendations (
Tsang et al 2006). Use the patient’s actual weight when calculating nutrient requirements, unless the actual weight is lower than the birth weight, in which case birth weight should be used.
Most preterm infants weighing less than 1500g will need parenteral nutrition (PN) to meet energy and nutrient requirements while enteral feeds are introduced and progressing (
Rationale 2).
Careful and early consideration should be given to the need for PN in preterm infants and once the decision to commence PN is made it should be started without undue delay and should meet the infant’s requirements (
Shaw and Lawson 2007).
Energy intakes above the infant’s requirements will lead to higher weight gain as a result of fat deposition and is not recommended (
Tsang et al 2006).
Higher energy requirements may be necessary in circumstances such as (
Tsang et al 2006):
- increased respiratory rate (as seen in Chronic Lung Disease [CLD])
- low body temperatures
- cardiac conditions
For infants with intra-uterine growth retardation (IUGR) or faltering growth the upper ranges of suggested nutrient requirements should be used ie 150kcal/kg/day of actual weight.
Protein accretion rate is achieved in preterm infants at around 2g/kg/day with a protein intake of 3-4g/kg/day as long as energy intake is at least 110kcal/kg/day (ie minimum protein: energy ratio 11-15%). There is incomplete utilisation of protein if more than 4.5g/kg/day is given (
Steward et al 2010).
Long-chained polyunsaturated fats (LCPs) are conditionally essential in preterm infants and are less efficiently absorbed from formula than breast milk (
Rationale 3).
Whilst breast milk contains
prebiotics, there is currently insufficient evidence for the addition of these to preterm infant formulas (
Steward et al 2010).
Choice of feed
Breast milk
Breast milk is the feed of choice for preterm infants (see clinical guideline: breastfeeding at GOSH). The benefits of human milk in preterm infants are well documented (
Agostoni et al 2010).
- Human milk contains immunological factors that potentially reduce the incidence of sepsis and Necrotising Enterocolitis (NEC) (Agostoni et al 2010).
- Strong evidence suggests that the absorption rate of nutrients from human milk is better than from breast milk substitutes.
- The enzymes, hormones and growth factors found in human milk play important roles in gastrointestinal growth and maturation and may accelerate the establishment of enteral feeding.
Facilities must be provided for mothers to breast feed their babies in privacy and comfort (see Clinical Guideline: Breast Feeding Guidance for Staff Assisting the Mother).
Babies who are < 35 weeks or too immature to suckle may have their mother’s expressed breast milk fed via an orogastric or nasogastric tube (see clinical guideline: breast milk expressing and handling) (
Rationale 4).
Mothers at high risk of Vitamin D deficiency who are expressing breast milk should be encouraged to take supplements (
Agostoni et al 2010) (
Rationale 5).
Breast feeding mothers who are vegan should be encouraged to take a Vitamin B12 supplement (
Agostoni et al 2010) (
Rationale 6).
Preterm infants > 1500g should aim for feeding volumes of 180ml/kg/day expressed breast milk (EBM) to ensure adequate intake of all nutrients. If it is not possible to feed at these volumes consider supplementation with breast milk fortifier (BMF) (see below).
Preterm infants < 1500g should have their EBM fortified (see below).
Breast milk fortifier
Instructions on adding BMF to EBM at ward level can be found in
clinical guideline: expressed breast milk: fortification.
Current available evidence suggests that the use of EBM fortifiers is safe for use in preterm infants and provide significant benefits in terms of growth and nutrition. Arguably, the widely reported benefits of the use of EBM fortifiers outweigh any certain suggestions of an increase in adverse outcomes as a result of the use of fortifiers (
Martin and Jackson 2011). However, care should be taken when considering fortifiers in high risk preterm infants. A multi-disciplinary team (MDT) decision would be appropriate in such instances. High risk infants include:
- < 27 weeks or < 1000g birth weight
- haemodynamically unstable on inotropes
- at risk for or confirmed NEC
- recent abdominal surgery
All infants should be receiving 150ml/kg/day of EBM before fortifier is considered (
Jones and King 2005).
All infants <1500g should be started on (BMF) two weeks after birth provided they are receiving at least 150ml/kg/day EBM (
Jones and King 2005) (
Rationale 7).
Fortification of EBM in infants < 1500g should continue until the infant is thriving with a weight around 2000-2500g and/or one month corrected age OR until the infant tolerates volumes of 180ml/kg/day.
In infants > 1500g who are failing to grow as well as expected on EBM alone consider fortifying their feeds:
- with BMF if they still < 37 weeks gestation
- with standard infant formula powder if they are now term
If there is a strong family history of atopy, use extensively hydrolysed protein infant formula to fortify EBM. Contact the dietitian (
Rationale 8).
Note: Extensively hydrolysed infant formula is designed for term infants and do not meet the recommended nutrient requirements for preterm infants.
If preterm formula is started in addition to EBM and BMF, the fortifier should be stopped once 50% of requirements are given as formula (
Rationale 9).
Monitor serum urea levels and avoid a steady decline and eventual drop to < 1.6mmol/L per day, which may indicate inadequate protein intake (interpret with caution especially in infants with dehydration, impaired renal function and steroid administration (
Rationale 10)). Therefore, ensure levels of 3g/kg/day of protein are given from EBM +/- fortifier (
Agostoni et al 2010; McClure and Newell 2000).
Donor expressed breast milk (DEBM)
When EBM is unavailable consider giving donor expressed breast milk (DEBM). See Clinical Guideline: Donor Expressed Breast Milk.
Every effort should be made to encourage mothers to express breast milk before donor EBM is used. It should also be considered that the process of donor milk banking affects the nutritional status of milk. It is unclear how such changes affect the health outcomes for recipients (
National Institute for Health and Clinical Excellence (NICE) 2010).
Donor EBM should be used short-term for the establishment of enteral feeds and close nutritional monitoring of the preterm infant receiving donor EBM is required.
Preterm formula
All infants < 2000g, who are not receiving EBM, should be started on a low osmolar preterm formula (SMA Gold Prem 1). This should continue until the infant is thriving and around 2000-2500g and / or discharged. Term formula can be used once the infant has reached 2000g and is thriving.
Other formulas
Extensively hydrolysed protein (eg Pepti-Junior, Pregestimil) or amino acid formulas (eg Neocate LCP) should not be routinely used in preterm infants (
Rationale 11).
Supplementation with vitamins and minerals
No vitamin supplements are required for preterm infants who are having 150ml/kg/day of preterm formula or fortified breast milk since these feeds will meet nutrient requirements.
All babies fed on unfortified breast milk, term infant formula; extensively hydrolysed protein or amino acid based formula should have the following supplements once they are receiving more than 50% of their fluid requirement as enteral feed.
| Vitamin/mineral | Requirement (Tsang et al 2006)
| Indication
| Dose per day
| Preparation
| Comments
|
Vitamin A
| 210-450ug/kg or 700-1500IU/kg
| See Rationale 12
| 400ug/1333IU | Abidec 0.6ml daily
| Discontinue at 12 months of age
|
Vitamin D
| 150-400IU/kg/day
| See Rationale 13
| 10ug/400IU | Abidec 0.6ml daily
| Discontinue at 12 months of age
|
Thiamine
| 180-240ug/kg
| See Rationale 14
| 400ug | Abidec 0.6ml daily
| Discontinue at 12 months of age
|
Riboflavin
| 250-360ug/kg
| See Rationale 14
| 800ug
| Abidec 0.6ml daily
| Discontinue at 12 months of age
|
Niacin
| 3.6-4.8mg/kg
| See Rationale 14
| 40mg
| Abidec 0.6ml daily
| Discontinue at 12 months of age
|
Vitamin C
| 18-24mg/kg
| See Rationale 14
| 40mg
| Abidec 0.6ml daily
| Discontinue at 12 months of age
|
Folic acid
| 25-50ug/kg
| See Rationale 14
| 50ug/day
| Folic acid syrup 0.2ml daily
| Discontinue at term age
|
Iron
** supplement in fortified and unfortified EBM
| 2-4mg/kg
| See Rationale 15
| 1ml or 5mg per day after two weeks of age
| Sytron syrup 1ml daily
| Discontinue at 12 months of age
|
Phosphate
* if serum level < 1.5mmol/L
| 60-140mg/kg
2-4.4mmol/kg
| See Rationale 15
| 1mmol/kg/day
| Sodium acid phosphate 1ml/kg/day
| Discontinue at one month corrected age
|
Calcium
* if serum level < 2.15mmol/L
| 100-220mg/kg
2.5-5.5mmol/kg.day
| See Rationale 15
| 1mmol/kg/day
| Calcium sandoz 2ml/kg/day
| Discontinue at term age or discharge from hospital
|
Table 1: Vitamin and mineral supplements for preterm babies on unfortified breast milk, term infant formula, extensively hydrolysed protein or amino acid based formula
Please note: Infants on fortified expressed breast milk may still need iron supplementation as breast milk fortifier contain no iron.
Additional information
- No additional Vitamin A supplementation is needed for preterm infants with CLD. A recent systematic review on the vitamin A supplementation in VLBW infants showed a reduction in oxygen requirements and death with early supplementation of Vitamin A, but raises the issue of the benefits of modest reduction balanced against lack of proven benefit and ethical acceptability of intramuscular injections. Longer-term data showed no evidence of either benefit or harm (Arslanoglu et al 2010).
- Avoid giving excess Vitamin D maximum 25ug/day (1000IU).
- No routine Vitamin E supplementation is required. Although high requirements have been shown in LBW infants, it seems as if they maintain their Vitamin E status on unsupplemented milk (Agostoni et al 2010). Pharmacological serum levels have been associated with an increased risk of sepsis and NEC and thus supplementation with pharmacological doses is not recommended (Agostoni et al 2010).
- Excessive calcium supplementation should be avoided to avoid problems with calcium soap formation and intestinal obstruction; oral supplementation decreases fat absorption from human milk and formula.
- Iron supplements should not be given with calcium or phosphorus as insoluble compound may be formed, reducing bioavailability (Agostoni et al 2010).
Initiation and progression of feeds
Enteral feeding should be started as soon as the infant’s clinical condition is considered stable, only when there is no abdominal distension or bilious aspirates.
Minimal enteral feeding or trophic feeds should ideally start within the first two to five days (
Rationale 16). Refer to
Appendix 2.
High risk infants should be assessed by the MDT before feeding is started.
Other advantages include (
Agostoni et al 2010):
- acceleration of maturation of the gastrointestinal tract with enhanced gut motility and increased lactase activity
- reduction in systemic infection due to reduced gut atrophy and bacterial translocation
- less dependence on PN, more rapid tolerance to full enteral feeding and earlier discharge
- improved weight gain
See frameworks for feed advancements (
Appendix 2,Appendix 3).
A standard feeding protocol has been shown to reduce the incidence of NEC (
Mactier and Weaver 2005).
In infants who are at risk of NEC minimal enteral feeds should be started early but not increased for the first few days (
Agostoni et al 2010).
Smaller infants should receive hourly feeds and increase to three- to four-hourly intervals as the infants grows (
Agostoni et al 2010).
Monitoring for feed intolerance
Note: The whole clinical picture should be evaluated together with these indicators to determine whether feeds are tolerated.
Indicators
- Infants < 1000g: >2ml gastric aspirates every four hours (10-20ml/kg/day)
- Infants > 1000g: >3ml gastric aspirates every four hours (15-20ml/kg/day)
Other indicators
- vomiting
- abdominal distension
- abdominal discolouration
- blood per rectum
- increase in stool frequency
Feeding route and frequency of feeds
There is no evidence to suggest an advantage of continuous feeding over bolus feeding (
Kamitsuka et al 2000).
Continuous feeding (rather than bolus feeding) may be useful in infants with gut resection, severe respiratory problems and those requiring naso-jejunal feeding (
Rationale 17).
All infants < 35 weeks gestation will require orogastric, or naso-gastric tube feeding (
Rationale 18).
Naso-jejunal feeding should be considered for preterm infants with severe gastro-oesophageal reflux.
Monitoring
Ensure use of UK-WHO Growth Charts on the unit:
- UK-WHO Neonatal and Infant Close Monitoring Chart (NICM) A4B (pack of 100) product code: UKWHOLBWA4B
- UK-WHO Neonatal and Infant Close Monitoring Chart (NICM) A4G (pack of 100) product code: UKWHOLBWA4G
All preterm infants should be corrected for gestational age until 24 months.
See
clinical guidelines for measuring a child: head circumference, height and length.
Measure
weight three times a week: Tuesday/Thursday/Sunday.
Plot birth weight on admission and weekly weights thereafter on centile charts (
Rationale 19).
Measure and plot
length weekly (Tuesdays) until 40 weeks post-conceptional age and then every two weeks until discharge (
Rationale 20).
Measure and plot
head circumference weekly: Tuesday. Use a non-stretch plasticised tape (
Rationale 21).
Target weight gain is an average weight gain of 15g/kg/day (
Rationale 22).
A reasonable target to aim for is to maintain the infant on the centile to which they have initially dropped, not their birth centile.
Indications for inadequate growth:
- consistent weight loss over several days (other than when diuresis is expected)
- when weight, length and/or head circumference velocity decreases over one week
- when weight velocity alone decreases over two weeks
(Decreased velocity is defined as growth at a lower rate than is needed to follow centile lines.)
Weekly monitoring of serum sodium, potassium, phosphorus, calcium, urea and creatinine, CRP, Hb as well as urinary sodium is required for nutritional assessment.
If the infant is receiving parenteral nutrition routine blood measurements are required (see
clinical guideline: parenteral nutrition).
Post-discharge nutrition
It is recognised that by the time of discharge many preterm infants demonstrate poor growth. It does not appear to be a predictor of continued poor growth post-discharge and most infants catch up.
Frequent exclusive breast feeding should be encouraged post-discharge with added supplements as per Table 1 above.
A phosphorus supplement may be needed until approximately one month post-term in breast fed infants with serum levels < 1.5 mmol/l at discharge.
Formula fed infants who are growth restricted at discharge should have a nutrient-enriched post-discharge formula (NEPDF) until three months corrected age (assess for each individual infant as some may need NEPDF until six months corrected age) (
Rationale 23).
Refer growth restricted infants to local paediatric dietitian for assessment of nutritional requirements and growth monitoring.
Formula fed infants who are not growth restricted at discharge would benefit from a NEPDF until 1 month corrected age (
Rationale 23).
After discontinuation of NEPDF, a term formula should be used until 12 – 18 months corrected age depending on the nutritional adequacy of the weaning diet.
Summary
Summary feeding flowcharts are given in
Appendix 3 and
Appendix 4.
Rationale 1: Preterm infants have limited nutrient stores as most nutrient stores are accreted in the last trimester (
Tsang et al 2006).
Rationale 2: Preterm infants have poor nutrient stores and an immature gastrointestinal tract (
Tsang et al 2006).
Rationale 3: A positive relationship has been found with visual development and cognitive development (
Steward et al 2010; Agostoni et al 2010).
Rationale 4: Babies develop suck-swallow-breathe pattern around 35-37 weeks gestation (
Tsang et al 2006).
Rationale 5: To ensure adequate Vitamin D intake of preterm infants receiving breast milk (
Agostoni et al 2010).
Rationale 6: Vegan mothers may produce milk with suboptimal Vitamin B12 levels (
Agostoni 2010).
Rationale 7: Nutrient levels in EBM may be in limiting amounts for many infants to meet increased preterm requirements (
Agostoni et al 2010).
Rationale 8: BMF contains cow’s milk derivatives which should be avoided.
Rationale 9: To avoid giving excess nutrients, especially protein as this can be considered undesirable (
Moro et al 1995).
Rationale 10: Low protein intake has been proven to be primary limiting factor responsible for growth failure in preterm infants (
Moro et al 1995).
Rationale 11: These formulas are designed for term infants and do not meet the particular special requirements for preterm infants (
Agostoni et al 2010).
Rationale 12: Vitamin A: Preterm infants appear to have limited fat absorption and therefore fat-soluble vitamin absorption (
Tsang et al 2006; Agostoni et al 2010). Preterm infants have lower or marginal Vitamin A stores than term infants (
Tsang et al 2006; Agostoni et al 2010) and are at high risk of vitamin A deficiency (Darlow and Graham 2002). Poor vitamin A status is associated with adverse respiratory outcome therefore higher requirements are required which may help reduce the incidence of CLD (
Agostoni et al 2010).
Rationale 13: Vitamin D: Vitamin D is important for supporting neuromuscular function and bone mineralisation (
Steward et al 2010). Vitamin D status of preterm infants in hospital was maintained in the United Kingdom when they received an intake of 400IU (10ug) per day (
Tsang et al 2006).
Rationale 14: Water soluble vitamins and folic acid: Unfortified breast milk does not contain adequate water-soluble vitamins and folic acid to meet requirements.
Rationale 15: Calcium, phosphorus and magnesium: the foetus acquires 80% of normal term body levels of calcium during the third trimester and preterm infants have very high requirements for calcium and other minerals for bone formation. Low plasma phosphate levels seem to indicate higher risk of bone disease in this group and the aim should be to keep levels > 1.8mmol/L. Serum levels should guide supplementation whatever the mode of feeding. Calcium, phosphorus and magnesium in breast milk is inadequate for infants < 1500g and/or 32 weeks gestation.
Rationale 16: Trophic feeding leads to improved energy intake, weight gain, milk tolerance, less sepsis and earlier hospital discharge. No increase in major complications including NEC is shown (
Tsang et al 2006; Martin and Jackson 2011).
Rationale 17: Bolus feeding has been associated with less feed tolerance and deterioration in respiratory function, resulting from gastric distension (
Tsang et al 2006).
Rationale 18: Preterm infants have an immature suck-swallow breathe pattern that is not developed until 35-37 weeks (
Tsang et al 2006).
Rationale 19: If the early weight loss seen post-birth is not plotted, subsequent weight gain appears poor over the following few weeks.
Rationale 20: Length measurement is essential for accurate growth assessment; it reflects both skeletal and organ growth
Rationale 21: The measurement of head circumference gives valuable information on brain growth and nutritional adequacy.
Rationale 22: To match intra-uterine growth rate, but may be difficult to achieve in more immature infants.
Rationale 23: Infants have an increased demand for nutrients as shown by very high volume consumption and accelerated rate of bone mineralisation at approximately 23-42 weeks post-conceptional age.
Reference 1:
American Academy of Pediatrics (2004) Committee on Fetus and Newborn.
Policy statement: Age terminology during the perinatal period. Pediatrics November 114(5) 1362 – 136.
Reference 2:
Tsang RC, Lucas A, Uauy R, Zlotkin S (2006)
Nutritional needs of the preterm infant: scientific basis and practical guidelines. Baltimore: Williams & Wilkins.
Reference 3:
Shaw V, Lawson M (2007)
Clinical Paediatric Dietetics 3rd Edition. Oxford: Blackwell Publishing.
Reference 4:
Steward JAD, Mason DG, Smith N, Protopapa K, Mason M (2010)
A Mixed Bag. An enquiry into the care of hospital patients receiving parenteral nutrition. A report by the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) London.
Reference 5:
Agostoni C, Buonocore G, Carnielli VP, De Curtis M, Darmaun D, Decsi T, Domellöf M, Embleton ND, Fusch C, Genzel-Boroviczeny O, Goulet O, Kalhan SC, Kolacek S, Koletzko B, Lapillonne A, Mihatsch W, Moreno L, Neu J, Poindexter B, Puntis J, Putet G, Rigo J, Riskin A, Salle B, Sauer P, Shamir R, Szajewska H, Thureen P, Turck D, van Goudoever JB, Ziegler EE (2010)
Enteral Nutrition Supply for Preterm Infants: Commentary From the European Society for Paediatric Gastroenterology, Hepatology and Nutrition Committee. (ESPGHAN). Journal of Paediatric Gastroenterology and Nutrition. 50: 1-9.
Reference 6:
Martin I, Jackson L (2011)
Is there an increased risk of necrotising enterocolitis in preterm infants whose mothers’ expressed breast milk is fortified with multicomponent fortifier? Arc. Dis Child 96: 1199-1201.
Reference 7:
Jones E, King C (2005)
Feeding and Nutrition in the preterm infant. Edinburgh: Elsevier Churchill Livingstone.
Reference 8:
McClure RJ, Newell SJ (2000)
Randomised controlled study of clinical outcome following trophic feeding. Arch Dis Child Fetal Neonatal Ed. Vol 82: F29-F33.
Reference 9:
National Institute for Health and Clinical Excellence (NICE)(2010)
Donor breast milk banks: the operation of donor milk bank services.
Reference 10:
Arslanoglu S; Moro G.E, Ziegler EE (2010)
Optimization of human milk fortification for preterm infants: new concepts and recommendations. J Perinatal Medicine. 38 233 – 238.
Reference 11:
Mactier H, Weaver LT (2005)
Vitamin A and the preterm infant: what we know, what we don’t know and what we need to know. Arch Dis Child Fetal Neonatal Ed. 90: F103-F108.
Reference 12:
Kamitsuka MD, Horton MK, Williams MA (2000)
The incidence of necrotizing enterocolitis after introducing standardised feeding schedules for infants between 1250g and 2500g and less than 35 weeks of gestation. Paediatrics Vol 105 No 2. Feb. 379 – 384
Reference 13:
Moro GE, Minoli I, Ostrom M, Jacobs JR, Picone TA, Räihä NC, Ziegler EE (1995)
Fortification of human milk: evaluation of a novel fortification scheme and of a new fortifier. J Paediatr Gastroenterol Nutri 20:162-172
Reference 14:
Darlow BA, Graham PJ (2002)
Vitamin A supplementation for preventing morbidity and mortality in very low birth weight infants. Cochrane Database Syst Review 4: CD000501
Reference 15:
Premji S, Chessel L. (2003)
Continuous nasogastric milk feeding versus intermitted bolus feeding for premature infants less than 1500g. Cochrane Database Syst Rev CD001819
Document control information
Lead author(s) Marlene Ellmer, Specialist Dietitian, Dietetics
Additional authors
Melanie Sklar, Principal Dietitian, Dietetics
Vanessa Shaw, Head of Dietetics, Dietetics
Document owner
Marlene Ellmer, Specialist Dietitian, Dietetics
Approved byClinical Practice Committee
First introduced: 1 December 2011
Date approved: 1 December 2011
Review schedule: Two years
Next review: 3 December 2013
Document version: 1.0
Replaces version: n/a
