- Email: [email protected]
Post-discharge nutrition for the preterm infant
Journal of Neonatal Nursing (2013) 19, 217e222
www.elsevier.com/jneo
Post-discharge nutrition for the preterm infant Anna Conrad* RD Imperial College Healthcare NHS Trust, St Mary’s Hospital, Praed St, London W2 1NY, UK Available online 3 April 2013
KEYWORDS Post-discharge; Vitamin A; Vitamin D; Iron; Breastfeeding; Formula; Growth
Abstract The preterm neonate, especially if born extremely premature and at a very low birthweight, is at risk of malnutrition postnatally. Lower stores of nutrients at birth, increased nutritional requirements, an immature gut and neonatal morbidities can mean that by the time the infant is ready for discharge they will have accumulated significant deficits in macro and micronutrients. The aim of nutrition post-discharge is to protect against nutritional deficiencies and support growth and development. Preterm infants discharged on breastmilk will need to be supplemented with vitamins A and D and iron. Preterm infants discharged on formula may require a nutrient enriched post-discharge formula which will provide increased nutrition until they can take sufficient volumes from a standard term formula. ª 2013 Neonatal Nurses Association. Published by Elsevier Ltd. All rights reserved.
Advances in neonatal medicine have resulted in the increased survival rates of babies born at lower gestations and lower birth weights. The last trimester of pregnancy is when the majority of nutrition is accreted. Therefore an infant born prematurely will be at a nutritional disadvantage compared to a well grown infant born at term. After birth, growth of the preterm infant is rapid and it should ideally double its body weight in 1e2 months, the term infant will take at least 5 months to double its weight. The preterm infant has high requirements for macronutrients (energy including fat, carbohydrate and protein) and
* Tel.: þ44 (0) 203 312 1127; fax: þ44 (0) 203 312 3377. E-mail address: [email protected].
micronutrients (vitamins, minerals, electrolytes and trace elements) to support this rapid growth. A challenging hospital course i.e. bouts of illness, delays in attaining full volumes of feed, malabsorption or underlying chronic illness can have deleterious effects on the preterm infant meeting its full nutritional needs and significant deficits in energy, protein and micronutrients can occur (Embleton et al., 2001). Growth faltering is common, particularly for the very preterm infant and those who experience neonatal morbidities such as chronic lung disease and sepsis (Adamkin, 2006; Ehrenkranz et al., 1999). If nutritional intake is suboptimal for any extended period of time the preterm infant can become anaemic (Raghavendra and Georgieff, 2009) and have a poorer neurodevelopmental
1355-1841/$ - see front matter ª 2013 Neonatal Nurses Association. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jnn.2013.03.001
218 outcome (Lucas et al., 1998). Under-mineralised bones have also been noted, although later peak bone mass may not be detrimentally affected (Fewtrell, 2011a,b). It is important to note that breastmilk is associated with long-term benefits for bone health and neurodevelopment, despite a low mineral content and poorer initial growth (Fewtrell, 2011a,b; Lucas et al., 1998). The aim of post-discharge nutrition is to support the ongoing nutritional needs of the preterm infant. Micronutrient supplements are needed for many, specifically those infants on breastmilk, and some may need a formula designed for preterm infants. There are currently no national guidelines regarding the use of supplementation and formulas post-discharge. Units either develop their own guidelines or will use guidelines developed within their network. There is little evidence on postdischarge requirements and practice varies across the country.
Growth Data on growth shows that a preterm infant has an initial weight loss post birth due to fluid loss. Growth velocity then stabilizes and they will tend to track 1e2 centiles below their birth centile (Ehrenkraz et al, 1999; Cole et al., 2011). Prior to discharge there may be a slowing of growth as the baby transitions from tube feeding to demand oral feeding if the volume of milk and nutritional intake reduces. Once babies are proficient at feeding and are taking adequate volumes and nutrition they will generally catch up and maintain a good growth trajectory. A drop of more than 2 centiles or a sustained drifting away from a centile is a likely indicator of inadequate nutrition and infants will need to be supported to catch up. This may extend well into the post-discharge period for an infant who has had a difficult hospital course or who is struggling to take sufficient volumes orally. It has been suggested that there is a ’critical window’ for catch-up growth after which time it is less likely to occur (Aggett et al., 2006). Very preterm infants may remain growth retarded for a number of years (Niklasson et al., 2003), although most will have caught up with their term counterparts by the age of 2 or 3 (Aggett et al., 2006). In the post-discharge period many babies will naturally cross centiles upwards even on modestly higher nutritional intakes. If the infant crosses past their birth centile this could simply mean that they did not reach their full growth potential in-utero
A. Conrad and are now correcting. However, it could mean that they are getting too much nutrition. There is some evidence to suggest that rapid growth in the early postnatal period may increase some cardiovascular disease risk factors due to the effects of early nutritional programming (Lucas, 2005). Risks to long-term health must be outweighed by the risks of poor growth and development caused by inadequate nutrition. However the promotion of accelerated growth through high level nutritional supplementation needs to be avoided. After discharge preterm babies should be weighed weekly, especially for breastfed babies, until growth is stable. Once catch up growth has been attained, growth monitoring for healthy preterm babies can be continued as for term babies. A length and head circumference carried out monthly will ensure that growth is proportional. Preterm infants should be plotted at the correct gestational age on the Neonatal and Infant Close Monitoring Charts, inserts for the Personal Child Health Record (red books) are available in the UK. Infants can be plotted on these charts up to 2 years of age, although healthy infants born before 32 weeks should only need to be corrected up to 1 year.
Milk Breastmilk The aim of any neonatal unit should be to send babies home demand breastfeeding. The short and long-term benefits of breastmilk for the preterm infant have been widely documented. In Europe many neonatal units will have discharged babies by 35e36 weeks postconceptual age, at weights of 1800e2100 g (Aggett et al., 2006). Most premature infants attain maximal oral feeding by 35e37 weeks (Jadcherla et al., 2010). This means that on discharge some preterm infants are still developing their oral feeding skills. They may need to be woken or encouraged to feed, and may not be able to manage sufficient volumes to meet their nutritional requirements. Mothers should be advised to express after feeds to ensure that the breast is fully emptied to maintain a good milk supply. The fortification of breastmilk can be useful to boost nutritional intake in babies struggling to manage sufficient volumes. The use of a breastmilk fortifier for a short period of time post-discharge has been advocated as it leads to better shortterm growth (McCormick et al., 2010; Cooke,
Post-discharge nutrition for the preterm infant 2011). It is not available on prescription and should be only be given under the guidance of a neonatal dietitian. If fortifier is needed a mother should be reassured that it is only required until her baby can manage to take bigger volumes at the breast. Care must be taken to ensure a mother never feels that the quality of her breastmilk, or the ability to feed her baby, is in question. Preterm infants, particularly those breastfeeding, must be monitored and supported postdischarge to ensure the infant is feeding well and thriving. Families who are given adequate breastfeeding support in the first weeks after discharge can achieve exclusive breastfeeding even with the smallest babies.
Infant formula Some babies will leave the neonatal unit on formula, either as an addition to, or as a substitute for, breastmilk. This can be through maternal choice or because the mother has not been able to produce adequate volumes of breastmilk. The suitability of formula for the preterm infant has been much debated. Standard term formula: the nutritional profile of term formula (67 kcal; 1.4 g protein/100 ml) is designed to support the needs of the term baby who can manage larger volumes than the average preterm baby at the same gestational age. A preterm infant who is struggling with volumes is unlikely to meet their nutritional requirements from a term formula. Some studies have found that preterm infants given term formula are at increased risk of poor nutritional status leading to neurodevelopmental impairment (Lucas et al., 1998) and poorer bone mineralisation and growth (Picauld et al., 2008). High energy formula: is designed to provide high amounts of energy and protein in small volumes (100 kcal; 2.5 g protein/100 ml). Infants have a calorie satiety mechanism and if feeding ad libitum will take a sufficient volume to meet their calorie requirements. With a high calorie formula this could result in smaller volumes of milk being taken and a restriction in the intake of protein and micronutrients, which would not be desirable for the preterm infant. However, a high energy formula might be useful if a preterm infant is fluid restricted or is unable to take large volumes of milk and it could avoid the need to tube feed. A dietitian should be involved in the decision to start a preterm baby on this type of formula. Preterm formula: is higher in macro and micronutrients than term formula but less so than high energy formula (80 kcal; 2.5 g protein/100 ml). It is
219 designed for preterm infants who have high nutritional requirements but are unable to take large volumes of milk. It is widely used on the neonatal unit when there is insufficient breastmilk. However, it is not prescribable in the community and is not for use post-discharge as the calorie satiety mechanism could limit the volume taken, compromising micronutrient intake. Post-discharge formula (PDF): is lower in macro and micronutrients than a preterm formula but higher than a term formula (75 kcal; 2.0 g protein/ 100 ml). It is designed for the preterm infant postdischarge who has increased nutritional requirements but is still only managing to take small volumes on demand. A PDF can support the nutritional requirements of the preterm infant until such time that they are taking sufficient volumes to meet their needs from a term formula. It is available on prescription. A Cochrane review of studies comparing the growth and development of preterm infants on standard term formula or nutrient-enriched postdischarge formula found no consistency of evidence (Young et al., 2012). Findings ranged from improved growth for infants on a nutrient-enriched formula (Lucas et al., 2001), to no significant difference (Atkinson et al., 2004), to improved growth for infants on a term formula (Koo and Hockman, 2006). However, the infants in the trials fed ad libitum and it is likely that those on a term formula took a greater volume to meet their energy requirements, thus ensuring that their protein and micronutrient intake was adequate to support growth and development. It has been found that preterm infants feeding ad libitum with a standard term formula can take volumes of 200e350 ml/kg to meet their energy requirements (Greer, 2007). Babies managing only small volumes will fall short in their nutritional intake if they are on a term formula. It would make sense therefore to support them with a nutrientenriched formula until they can take adequate volumes. The use of a PDF has been advocated by ESPGHAN (Aggett et al., 2006) for preterm infants with a suboptimal weight at discharge to at least 40e52 weeks post-conceptual age (term-12 weeks corrected gestational age). Local practice is to use a PDF on discharge for all babies born before 35 weeks needing formula and to be continued until 3 months corrected age at which time most can manage larger volumes and attain adequate nutrition from a term formula. If there is any concern about growth then a PDF can be continued until 6 months corrected age.
220
Vitamins and minerals Accretion of micronutrients occurs predominately in the last trimester which means that the stores of micronutrients in a preterm infant will be lower than that of an infant born at term. In the early postnatal period low intraluminal bile acid concentrations and an immature gut result in a reduced ability to absorb fat and the fat soluble vitamins (Agostoni et al., 2010). Vitamins A and D and iron are routinely prescribed on discharge for preterm babies on breastmilk.
Vitamin A Vitamin A is needed for cell differentiation and immunity, and is involved in ocular and respiratory development. Preterm infants are born with low hepatic stores and low plasma retinol concentrations (Mactier and Weaver, 2005). Deficiency is associated with an increased risk of lung disease and retinopathy of prematurity in the preterm neonate (Mactier and Weaver, 2005). There is not enough vitamin A in human milk to support the needs of the preterm infant and those infants on breastmilk will need supplementation (Agostoni et al., 2010). Recommendations for supplementation have increased from 700 to 1500 iu/kg/d (Tsang et al., 2005) to 1332e3300 iu/ kg/d (Agostoni et al., 2010). It has been suggested that 5000 iu/d for the first month of life is needed to normalise levels and thereafter 3000 iu/d should be given (Salle et al., 2007). There are no definitive recommendations for vitamin A supplementation post-discharge as to the target amount or period of administration. 1000 iu/ d until 2 months chronological age has been suggested (Greer, 2007); although the author admits this dose may be inadequate. A dose of 3000 iu/d given until 6 months of age has also been recommended (Salle et al., 2007). Vitamin A is usually given as part of a multivitamin and so the dose will be dependent upon the specific supplement prescribed. Local practice is to supplement babies born before 35 weeks who are receiving any breastmilk with a tri-vitamin (A, C and D) on discharge. This is continued until the infant is 12 months old, unless they change to all formula when supplements are not needed.
A. Conrad absorption is dependent upon vitamin D and uncorrected vitamin D deficiency can result in osteopenia of prematurity. There is insufficient vitamin D in breastmilk for the preterm infant and infants on breastmilk will require supplementation from the early post-natal period. The recommendations for supplementation of vitamin D vary from 200 to 1000 iu/d (Tsang et al., 2005) to 800e1000 iu/d (Agostoni et al., 2010). There is currently little evidence for the higher doses of vitamin D and many neonatal units in the UK do not supplement more than 400 iu/d. However, preterm babies born to vitamin D deficient mothers may benefit from supplementation of at least 800 iu/d (Agostoni et al., 2010). Recommendations for the length of administration of vitamin D post-discharge include giving it for 6 months (Salle et al., 2007) and the rather less definitive to give it ’during the first months of life’ (Agostoni et al., 2010). Local practice is to supplement all preterm babies born before 35 weeks who are on breastmilk with a tri-vitamin supplement on discharge providing 400 iu/d vitamin D. Those babies who are taking formula may also need additional supplementation if they are unable to meet their vitamin D requirements e.g. a 2 kg baby taking 160 ml/kg of a nutrient enriched post-discharge formula will only be getting around 220 iu/d vitamin D. Supplementation of vitamin D is continued for 12 months unless the infant is taking adequate amounts of formula when additional supplementation is not necessary. Once the infant is 12 months of age Department of Health (DoH) 2012 guidance on vitamin D should be followed: supplementation of vitamin D (7.0e8.5 ug/280e340 iu/d) up to the age of 5 years for all babies taking <500 ml/d infant formula i.e. those on breastmilk, cow’s milk or cow’s milk alternative (e.g. soya or oat milk). DoH guidance recommends that all pregnant and breastfeeding women take a daily dose of 10 ug (400 iu) of vitamin D. Although this will not increase the vitamin D intake of the breastfed child it will correct any maternal deficiency and protect future pregnancies. Phosphorus, another essential mineral in bone development, is occasionally given at discharge depending upon serum levels. If a baby is discharged on breastmilk fortifier (BMF) they will be getting increased phosphorus in addition to other nutrients.
Vitamin D Iron Vitamin D supports a range of physiological processes including bone mineralisation and neuromuscular function (Agostoni et al., 2010). Calcium
Preterm infants have lower stores of iron than term infants (Dall’Agnola and Beghini, 2009). It is
Post-discharge nutrition for the preterm infant an essential nutrient for neurodevelopment, and deficiency can lead to irreversible long-term neurodevelopmental impairment, as well as poor growth, altered immunity and temperature instability (Raghavendra and Georgieff, 2009). Breastmilk does not contain enough iron for the preterm infant and the infant’s own low stores mean that supplementation is essential to prevent deficiency. Supplementation of <2 mg/kg/d has led to iron deficiency in infants with a birthweight of <1800 g (Agostoni et al., 2010). The European Society for Pediatric Gastroenterology, Heptology and Nutrition (ESPGHAN) recommend to start 2e3 mg/kg/d of iron at 2e6 weeks, when it can be utilized, and to continue until 6e12 months of age depending on diet (Agostoni et al., 2010). Local practice is to supplement babies born <35 weeks with a 5.5 mg dose of iron from 3 weeks post-birth until 12 months chronological age if they are on breastmilk þ/ formula (depending on iron intake from the formula) to ensure adequate iron intake. The dose of iron per kg body weight will reduce as the infant gains weight but supplementation will help to support those babies who do not progress in a timely way onto an iron rich weaning diet. Babies who end up on all formula are unlikely to need an additional iron supplement depending upon the iron content of the formula and the volume of formula taken. A nutrient-enriched postdischarge formula has a higher iron content per 100 ml than a term formula and may be better suited to infants who are only managing smaller volumes to ensure an adequate iron intake.
Monitoring Preterm babies are a vulnerable group that will need close monitoring post-discharge. The parents, GP and health visitor should be given a clear care plan including the use of supplementation and/or formula to ensure appropriate ongoing care. Growth will need to be monitored as outlined previously to ensure that both under and overnutrition are avoided. Any concerns should be fed back to the discharging unit so that appropriate support can be given. The introduction of solids can occur between 5 and 8 months actual age but infants should be at least 3 months corrected to allow for motor development of head control. Detailed information on weaning the preterm infant can be found in the Joint consensus statement on weaning preterm babies (2011).
221
Conflict of interest I declare no conflict of interest.
Role of funding source I declare no sponsor involvement.
Acknowledgements I express gratitude to Caroline King, Chief Paediatric and Neonatal Dietitian, at Imperial College Healthcare NHS Trust, for her comments and support.
References Adamkin, D.H., 2006. Postdischarge nutritional therapy. Journal of Perinatology 26, S27eS30. Aggett, P., Agostoni, C., Axelsson, I., De Curtis, M., Goulet, O., Hernell, O., Koletzko, B., Lafeber, H., Michaelsen, K., Puntis, J., Rigo, J., Shamir, R., Szajewska, H., Turck, D., Weaver, L., 2006. Feeding preterm infants after hospital discharge: a commentary by the ESPGHAN committee on nutrition. Journal of Pediatric Gastroenterology Nutrition 42, 596e603. Agostoni, C., Buonocore, G., Carnielli, V.P., De Curtis, M., Darmaun, D., Decsi, T., Domellof, M., Embleton, N.D., Fusch, C., et al., 2010. Enteral nutrient supply for preterm infants: commentary from the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition committee on nutrition. Journal of Pediatric Gastroenterology Nutrition 50, 1e9. Atkinson, S.A., Paes, B., Saigal, S., Hussey, T., Lee, D., 2004. Nutrient enriched discharge formula compared to standard term formula does not benefit growth, bone mineral accretion or trace element status in preterm small for gestational age (SGA) infants to one year corrected age: a RCT. Pediatric Research 55, 383A. Cole, T., Statnikov, Y., Santhakumaran, S., et al., 2011. Postnatal weight gain after very preterm birth: a UK population study. Archives of Disease Childhood 96 (suppl 1), A1eA100. Cooke, R., 2011. Nutrition of preterm infants after discharge. Annals of Nutrition and Metabolism 58 (suppl 1), 32e36. Dall’Agnola, A., Beghini, L., 2009. Post-discharge supplementation of vitamins and minerals for preterm neonates. Early Human Development 85, S27eS29. Department of Health., 2012. http://www.dh.gov.uk/health/ 2012/02/advice-vitamin-d/. Ehrenkranz, R., Younes, N., Lemons, J., et al., 1999. Longitudinal growth of hospitalized very low birth weight infants. Pediatrics 104, 280e289. Embleton, N., Pang, N., Cooke, R., 2001. Post malnutrition and growth retardation: an inevitable consequence of current recommendations in preterm infants? Pediatrics 107, 270e273. Fewtrell, M., 2011a. Early nutritional predictors of long-term bone health in preterm infants. Current Opinion in Clinical Nutrition and Metabolic Care 14 (3), 297e301.
222
A. Conrad
Fewtrell, M.S., 2011b. Does early nutrition program later bone health in preterm infants? American Journal of Clinical Nutrition 94 (6 Suppl), 1870Se1873S. Greer, F., 2007. Post-discharge nutrition: what does the evidence support? Seminars in Perinatology 31, 89e95. Jadcherla, S.R., Wang, M., Vijayapal, A.S., Leuthner, S.R., 2010. Impact of prematurity and co-morbidities on feeding milestones in neonates: a retrospective study. Journal of Perinatology 30 (3), 201e208. Joint Consensus Statement on Weaning Preterm Babies, 2011. Access via BAPM website. www.bapm.org/nutrition. Koo, W.W., Hockman, E.M., 2006. Posthospital discharge feeding for preterm infants: effects of standard compared with enriched milk formula on growth, bone mass, and body composition. American Journal of Clinical Nutrition 84, 1357e1364. Lucas, A., 2005. Long-term programming effects of early nutrition. Implications for the preterm infant. Journal of Perinatology 25, S2eS6. Lucas, A., Morely, R., Cole, T., 1998. Randomised trial of early diet in preterm babies and later intelligent quotient. BMJ 317, 1481e1487. Lucas, A., Fewtrell, M.S., Morely, R., Singhal, A., Abbott, R.A., Isaacs, E., et al., 2001. Randomised trial of nutrientenriched formula versus standard formula for postdischarge preterm infants. Pediatrics 108, 703e711. Mactier, H., Weaver, L.T., 2005. Vitamin A and preterm infants: what we know, what we don’t know, and what we need to
know. Archives of Disease in Childhood Fetal Neonatal Ed 90, F103eF108. McCormick, F.M., Henderson, G., Fahey, T., McGuire, W., 2010. Multinutrient fortification of human breast milk for preterm infants following hospital discharge (review). The Cochrane Database Syst Rev (7), CD004866. Nikklasson, A., Engstrom, E., Hard, A., Albertsson Wikland, K., Strom, A., 2003. Growth in very preterm children: a longitudinal study. Pediatric Research 54, 899e905. Picauld, J., Decullier, E., Plan, O., Pidoux, O., Bin-Dorel, S., Van Egroo, L.D., Chapud, F., Claris, O., 2008. Growth and bone mineralisation in preterm infants fed preterm formula or standard term formula after discharge. Journal of Pediatrics 153, 616e621. Raghavendra, R., Georgieff, M.K., March 2009. Iron therapy for preterm infants. Clinics in Perinatology 36 (1), 27e42. Salle, B.L., Delvin, E., Claris, O., Hascoet, J.M., Levy, E., Dec 2007. Is it justifiable to administrate vitamin A, E and D for 6 months in the premature infant? Arch Pediatric 14 (12), 1408e1412. Tsang, R.C., Uauy, R., Koletzko, B., Zlotkin, S.H., 2005. Nutrition of the Preterm Infant: Scientific Basis and Practical Guidelines, second ed. Digital Education Publishing, Cincinnati. Young, L., Morgan, J., McCormick, F.M., McGuire, W., 2012 Mar 14. Nutrient-enriched formula versus standard term formula for preterm infants following hospital discharge. Cochrane Database Syst Rev 3, CD004696.
Available online at www.sciencedirect.com
www.elsevier.com/jneo
Post-discharge nutrition for the preterm infant Anna Conrad* RD Imperial College Healthcare NHS Trust, St Mary’s Hospital, Praed St, London W2 1NY, UK Available online 3 April 2013
KEYWORDS Post-discharge; Vitamin A; Vitamin D; Iron; Breastfeeding; Formula; Growth
Abstract The preterm neonate, especially if born extremely premature and at a very low birthweight, is at risk of malnutrition postnatally. Lower stores of nutrients at birth, increased nutritional requirements, an immature gut and neonatal morbidities can mean that by the time the infant is ready for discharge they will have accumulated significant deficits in macro and micronutrients. The aim of nutrition post-discharge is to protect against nutritional deficiencies and support growth and development. Preterm infants discharged on breastmilk will need to be supplemented with vitamins A and D and iron. Preterm infants discharged on formula may require a nutrient enriched post-discharge formula which will provide increased nutrition until they can take sufficient volumes from a standard term formula. ª 2013 Neonatal Nurses Association. Published by Elsevier Ltd. All rights reserved.
Advances in neonatal medicine have resulted in the increased survival rates of babies born at lower gestations and lower birth weights. The last trimester of pregnancy is when the majority of nutrition is accreted. Therefore an infant born prematurely will be at a nutritional disadvantage compared to a well grown infant born at term. After birth, growth of the preterm infant is rapid and it should ideally double its body weight in 1e2 months, the term infant will take at least 5 months to double its weight. The preterm infant has high requirements for macronutrients (energy including fat, carbohydrate and protein) and
* Tel.: þ44 (0) 203 312 1127; fax: þ44 (0) 203 312 3377. E-mail address: [email protected].
micronutrients (vitamins, minerals, electrolytes and trace elements) to support this rapid growth. A challenging hospital course i.e. bouts of illness, delays in attaining full volumes of feed, malabsorption or underlying chronic illness can have deleterious effects on the preterm infant meeting its full nutritional needs and significant deficits in energy, protein and micronutrients can occur (Embleton et al., 2001). Growth faltering is common, particularly for the very preterm infant and those who experience neonatal morbidities such as chronic lung disease and sepsis (Adamkin, 2006; Ehrenkranz et al., 1999). If nutritional intake is suboptimal for any extended period of time the preterm infant can become anaemic (Raghavendra and Georgieff, 2009) and have a poorer neurodevelopmental
1355-1841/$ - see front matter ª 2013 Neonatal Nurses Association. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jnn.2013.03.001
218 outcome (Lucas et al., 1998). Under-mineralised bones have also been noted, although later peak bone mass may not be detrimentally affected (Fewtrell, 2011a,b). It is important to note that breastmilk is associated with long-term benefits for bone health and neurodevelopment, despite a low mineral content and poorer initial growth (Fewtrell, 2011a,b; Lucas et al., 1998). The aim of post-discharge nutrition is to support the ongoing nutritional needs of the preterm infant. Micronutrient supplements are needed for many, specifically those infants on breastmilk, and some may need a formula designed for preterm infants. There are currently no national guidelines regarding the use of supplementation and formulas post-discharge. Units either develop their own guidelines or will use guidelines developed within their network. There is little evidence on postdischarge requirements and practice varies across the country.
Growth Data on growth shows that a preterm infant has an initial weight loss post birth due to fluid loss. Growth velocity then stabilizes and they will tend to track 1e2 centiles below their birth centile (Ehrenkraz et al, 1999; Cole et al., 2011). Prior to discharge there may be a slowing of growth as the baby transitions from tube feeding to demand oral feeding if the volume of milk and nutritional intake reduces. Once babies are proficient at feeding and are taking adequate volumes and nutrition they will generally catch up and maintain a good growth trajectory. A drop of more than 2 centiles or a sustained drifting away from a centile is a likely indicator of inadequate nutrition and infants will need to be supported to catch up. This may extend well into the post-discharge period for an infant who has had a difficult hospital course or who is struggling to take sufficient volumes orally. It has been suggested that there is a ’critical window’ for catch-up growth after which time it is less likely to occur (Aggett et al., 2006). Very preterm infants may remain growth retarded for a number of years (Niklasson et al., 2003), although most will have caught up with their term counterparts by the age of 2 or 3 (Aggett et al., 2006). In the post-discharge period many babies will naturally cross centiles upwards even on modestly higher nutritional intakes. If the infant crosses past their birth centile this could simply mean that they did not reach their full growth potential in-utero
A. Conrad and are now correcting. However, it could mean that they are getting too much nutrition. There is some evidence to suggest that rapid growth in the early postnatal period may increase some cardiovascular disease risk factors due to the effects of early nutritional programming (Lucas, 2005). Risks to long-term health must be outweighed by the risks of poor growth and development caused by inadequate nutrition. However the promotion of accelerated growth through high level nutritional supplementation needs to be avoided. After discharge preterm babies should be weighed weekly, especially for breastfed babies, until growth is stable. Once catch up growth has been attained, growth monitoring for healthy preterm babies can be continued as for term babies. A length and head circumference carried out monthly will ensure that growth is proportional. Preterm infants should be plotted at the correct gestational age on the Neonatal and Infant Close Monitoring Charts, inserts for the Personal Child Health Record (red books) are available in the UK. Infants can be plotted on these charts up to 2 years of age, although healthy infants born before 32 weeks should only need to be corrected up to 1 year.
Milk Breastmilk The aim of any neonatal unit should be to send babies home demand breastfeeding. The short and long-term benefits of breastmilk for the preterm infant have been widely documented. In Europe many neonatal units will have discharged babies by 35e36 weeks postconceptual age, at weights of 1800e2100 g (Aggett et al., 2006). Most premature infants attain maximal oral feeding by 35e37 weeks (Jadcherla et al., 2010). This means that on discharge some preterm infants are still developing their oral feeding skills. They may need to be woken or encouraged to feed, and may not be able to manage sufficient volumes to meet their nutritional requirements. Mothers should be advised to express after feeds to ensure that the breast is fully emptied to maintain a good milk supply. The fortification of breastmilk can be useful to boost nutritional intake in babies struggling to manage sufficient volumes. The use of a breastmilk fortifier for a short period of time post-discharge has been advocated as it leads to better shortterm growth (McCormick et al., 2010; Cooke,
Post-discharge nutrition for the preterm infant 2011). It is not available on prescription and should be only be given under the guidance of a neonatal dietitian. If fortifier is needed a mother should be reassured that it is only required until her baby can manage to take bigger volumes at the breast. Care must be taken to ensure a mother never feels that the quality of her breastmilk, or the ability to feed her baby, is in question. Preterm infants, particularly those breastfeeding, must be monitored and supported postdischarge to ensure the infant is feeding well and thriving. Families who are given adequate breastfeeding support in the first weeks after discharge can achieve exclusive breastfeeding even with the smallest babies.
Infant formula Some babies will leave the neonatal unit on formula, either as an addition to, or as a substitute for, breastmilk. This can be through maternal choice or because the mother has not been able to produce adequate volumes of breastmilk. The suitability of formula for the preterm infant has been much debated. Standard term formula: the nutritional profile of term formula (67 kcal; 1.4 g protein/100 ml) is designed to support the needs of the term baby who can manage larger volumes than the average preterm baby at the same gestational age. A preterm infant who is struggling with volumes is unlikely to meet their nutritional requirements from a term formula. Some studies have found that preterm infants given term formula are at increased risk of poor nutritional status leading to neurodevelopmental impairment (Lucas et al., 1998) and poorer bone mineralisation and growth (Picauld et al., 2008). High energy formula: is designed to provide high amounts of energy and protein in small volumes (100 kcal; 2.5 g protein/100 ml). Infants have a calorie satiety mechanism and if feeding ad libitum will take a sufficient volume to meet their calorie requirements. With a high calorie formula this could result in smaller volumes of milk being taken and a restriction in the intake of protein and micronutrients, which would not be desirable for the preterm infant. However, a high energy formula might be useful if a preterm infant is fluid restricted or is unable to take large volumes of milk and it could avoid the need to tube feed. A dietitian should be involved in the decision to start a preterm baby on this type of formula. Preterm formula: is higher in macro and micronutrients than term formula but less so than high energy formula (80 kcal; 2.5 g protein/100 ml). It is
219 designed for preterm infants who have high nutritional requirements but are unable to take large volumes of milk. It is widely used on the neonatal unit when there is insufficient breastmilk. However, it is not prescribable in the community and is not for use post-discharge as the calorie satiety mechanism could limit the volume taken, compromising micronutrient intake. Post-discharge formula (PDF): is lower in macro and micronutrients than a preterm formula but higher than a term formula (75 kcal; 2.0 g protein/ 100 ml). It is designed for the preterm infant postdischarge who has increased nutritional requirements but is still only managing to take small volumes on demand. A PDF can support the nutritional requirements of the preterm infant until such time that they are taking sufficient volumes to meet their needs from a term formula. It is available on prescription. A Cochrane review of studies comparing the growth and development of preterm infants on standard term formula or nutrient-enriched postdischarge formula found no consistency of evidence (Young et al., 2012). Findings ranged from improved growth for infants on a nutrient-enriched formula (Lucas et al., 2001), to no significant difference (Atkinson et al., 2004), to improved growth for infants on a term formula (Koo and Hockman, 2006). However, the infants in the trials fed ad libitum and it is likely that those on a term formula took a greater volume to meet their energy requirements, thus ensuring that their protein and micronutrient intake was adequate to support growth and development. It has been found that preterm infants feeding ad libitum with a standard term formula can take volumes of 200e350 ml/kg to meet their energy requirements (Greer, 2007). Babies managing only small volumes will fall short in their nutritional intake if they are on a term formula. It would make sense therefore to support them with a nutrientenriched formula until they can take adequate volumes. The use of a PDF has been advocated by ESPGHAN (Aggett et al., 2006) for preterm infants with a suboptimal weight at discharge to at least 40e52 weeks post-conceptual age (term-12 weeks corrected gestational age). Local practice is to use a PDF on discharge for all babies born before 35 weeks needing formula and to be continued until 3 months corrected age at which time most can manage larger volumes and attain adequate nutrition from a term formula. If there is any concern about growth then a PDF can be continued until 6 months corrected age.
220
Vitamins and minerals Accretion of micronutrients occurs predominately in the last trimester which means that the stores of micronutrients in a preterm infant will be lower than that of an infant born at term. In the early postnatal period low intraluminal bile acid concentrations and an immature gut result in a reduced ability to absorb fat and the fat soluble vitamins (Agostoni et al., 2010). Vitamins A and D and iron are routinely prescribed on discharge for preterm babies on breastmilk.
Vitamin A Vitamin A is needed for cell differentiation and immunity, and is involved in ocular and respiratory development. Preterm infants are born with low hepatic stores and low plasma retinol concentrations (Mactier and Weaver, 2005). Deficiency is associated with an increased risk of lung disease and retinopathy of prematurity in the preterm neonate (Mactier and Weaver, 2005). There is not enough vitamin A in human milk to support the needs of the preterm infant and those infants on breastmilk will need supplementation (Agostoni et al., 2010). Recommendations for supplementation have increased from 700 to 1500 iu/kg/d (Tsang et al., 2005) to 1332e3300 iu/ kg/d (Agostoni et al., 2010). It has been suggested that 5000 iu/d for the first month of life is needed to normalise levels and thereafter 3000 iu/d should be given (Salle et al., 2007). There are no definitive recommendations for vitamin A supplementation post-discharge as to the target amount or period of administration. 1000 iu/ d until 2 months chronological age has been suggested (Greer, 2007); although the author admits this dose may be inadequate. A dose of 3000 iu/d given until 6 months of age has also been recommended (Salle et al., 2007). Vitamin A is usually given as part of a multivitamin and so the dose will be dependent upon the specific supplement prescribed. Local practice is to supplement babies born before 35 weeks who are receiving any breastmilk with a tri-vitamin (A, C and D) on discharge. This is continued until the infant is 12 months old, unless they change to all formula when supplements are not needed.
A. Conrad absorption is dependent upon vitamin D and uncorrected vitamin D deficiency can result in osteopenia of prematurity. There is insufficient vitamin D in breastmilk for the preterm infant and infants on breastmilk will require supplementation from the early post-natal period. The recommendations for supplementation of vitamin D vary from 200 to 1000 iu/d (Tsang et al., 2005) to 800e1000 iu/d (Agostoni et al., 2010). There is currently little evidence for the higher doses of vitamin D and many neonatal units in the UK do not supplement more than 400 iu/d. However, preterm babies born to vitamin D deficient mothers may benefit from supplementation of at least 800 iu/d (Agostoni et al., 2010). Recommendations for the length of administration of vitamin D post-discharge include giving it for 6 months (Salle et al., 2007) and the rather less definitive to give it ’during the first months of life’ (Agostoni et al., 2010). Local practice is to supplement all preterm babies born before 35 weeks who are on breastmilk with a tri-vitamin supplement on discharge providing 400 iu/d vitamin D. Those babies who are taking formula may also need additional supplementation if they are unable to meet their vitamin D requirements e.g. a 2 kg baby taking 160 ml/kg of a nutrient enriched post-discharge formula will only be getting around 220 iu/d vitamin D. Supplementation of vitamin D is continued for 12 months unless the infant is taking adequate amounts of formula when additional supplementation is not necessary. Once the infant is 12 months of age Department of Health (DoH) 2012 guidance on vitamin D should be followed: supplementation of vitamin D (7.0e8.5 ug/280e340 iu/d) up to the age of 5 years for all babies taking <500 ml/d infant formula i.e. those on breastmilk, cow’s milk or cow’s milk alternative (e.g. soya or oat milk). DoH guidance recommends that all pregnant and breastfeeding women take a daily dose of 10 ug (400 iu) of vitamin D. Although this will not increase the vitamin D intake of the breastfed child it will correct any maternal deficiency and protect future pregnancies. Phosphorus, another essential mineral in bone development, is occasionally given at discharge depending upon serum levels. If a baby is discharged on breastmilk fortifier (BMF) they will be getting increased phosphorus in addition to other nutrients.
Vitamin D Iron Vitamin D supports a range of physiological processes including bone mineralisation and neuromuscular function (Agostoni et al., 2010). Calcium
Preterm infants have lower stores of iron than term infants (Dall’Agnola and Beghini, 2009). It is
Post-discharge nutrition for the preterm infant an essential nutrient for neurodevelopment, and deficiency can lead to irreversible long-term neurodevelopmental impairment, as well as poor growth, altered immunity and temperature instability (Raghavendra and Georgieff, 2009). Breastmilk does not contain enough iron for the preterm infant and the infant’s own low stores mean that supplementation is essential to prevent deficiency. Supplementation of <2 mg/kg/d has led to iron deficiency in infants with a birthweight of <1800 g (Agostoni et al., 2010). The European Society for Pediatric Gastroenterology, Heptology and Nutrition (ESPGHAN) recommend to start 2e3 mg/kg/d of iron at 2e6 weeks, when it can be utilized, and to continue until 6e12 months of age depending on diet (Agostoni et al., 2010). Local practice is to supplement babies born <35 weeks with a 5.5 mg dose of iron from 3 weeks post-birth until 12 months chronological age if they are on breastmilk þ/ formula (depending on iron intake from the formula) to ensure adequate iron intake. The dose of iron per kg body weight will reduce as the infant gains weight but supplementation will help to support those babies who do not progress in a timely way onto an iron rich weaning diet. Babies who end up on all formula are unlikely to need an additional iron supplement depending upon the iron content of the formula and the volume of formula taken. A nutrient-enriched postdischarge formula has a higher iron content per 100 ml than a term formula and may be better suited to infants who are only managing smaller volumes to ensure an adequate iron intake.
Monitoring Preterm babies are a vulnerable group that will need close monitoring post-discharge. The parents, GP and health visitor should be given a clear care plan including the use of supplementation and/or formula to ensure appropriate ongoing care. Growth will need to be monitored as outlined previously to ensure that both under and overnutrition are avoided. Any concerns should be fed back to the discharging unit so that appropriate support can be given. The introduction of solids can occur between 5 and 8 months actual age but infants should be at least 3 months corrected to allow for motor development of head control. Detailed information on weaning the preterm infant can be found in the Joint consensus statement on weaning preterm babies (2011).
221
Conflict of interest I declare no conflict of interest.
Role of funding source I declare no sponsor involvement.
Acknowledgements I express gratitude to Caroline King, Chief Paediatric and Neonatal Dietitian, at Imperial College Healthcare NHS Trust, for her comments and support.
References Adamkin, D.H., 2006. Postdischarge nutritional therapy. Journal of Perinatology 26, S27eS30. Aggett, P., Agostoni, C., Axelsson, I., De Curtis, M., Goulet, O., Hernell, O., Koletzko, B., Lafeber, H., Michaelsen, K., Puntis, J., Rigo, J., Shamir, R., Szajewska, H., Turck, D., Weaver, L., 2006. Feeding preterm infants after hospital discharge: a commentary by the ESPGHAN committee on nutrition. Journal of Pediatric Gastroenterology Nutrition 42, 596e603. Agostoni, C., Buonocore, G., Carnielli, V.P., De Curtis, M., Darmaun, D., Decsi, T., Domellof, M., Embleton, N.D., Fusch, C., et al., 2010. Enteral nutrient supply for preterm infants: commentary from the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition committee on nutrition. Journal of Pediatric Gastroenterology Nutrition 50, 1e9. Atkinson, S.A., Paes, B., Saigal, S., Hussey, T., Lee, D., 2004. Nutrient enriched discharge formula compared to standard term formula does not benefit growth, bone mineral accretion or trace element status in preterm small for gestational age (SGA) infants to one year corrected age: a RCT. Pediatric Research 55, 383A. Cole, T., Statnikov, Y., Santhakumaran, S., et al., 2011. Postnatal weight gain after very preterm birth: a UK population study. Archives of Disease Childhood 96 (suppl 1), A1eA100. Cooke, R., 2011. Nutrition of preterm infants after discharge. Annals of Nutrition and Metabolism 58 (suppl 1), 32e36. Dall’Agnola, A., Beghini, L., 2009. Post-discharge supplementation of vitamins and minerals for preterm neonates. Early Human Development 85, S27eS29. Department of Health., 2012. http://www.dh.gov.uk/health/ 2012/02/advice-vitamin-d/. Ehrenkranz, R., Younes, N., Lemons, J., et al., 1999. Longitudinal growth of hospitalized very low birth weight infants. Pediatrics 104, 280e289. Embleton, N., Pang, N., Cooke, R., 2001. Post malnutrition and growth retardation: an inevitable consequence of current recommendations in preterm infants? Pediatrics 107, 270e273. Fewtrell, M., 2011a. Early nutritional predictors of long-term bone health in preterm infants. Current Opinion in Clinical Nutrition and Metabolic Care 14 (3), 297e301.
222
A. Conrad
Fewtrell, M.S., 2011b. Does early nutrition program later bone health in preterm infants? American Journal of Clinical Nutrition 94 (6 Suppl), 1870Se1873S. Greer, F., 2007. Post-discharge nutrition: what does the evidence support? Seminars in Perinatology 31, 89e95. Jadcherla, S.R., Wang, M., Vijayapal, A.S., Leuthner, S.R., 2010. Impact of prematurity and co-morbidities on feeding milestones in neonates: a retrospective study. Journal of Perinatology 30 (3), 201e208. Joint Consensus Statement on Weaning Preterm Babies, 2011. Access via BAPM website. www.bapm.org/nutrition. Koo, W.W., Hockman, E.M., 2006. Posthospital discharge feeding for preterm infants: effects of standard compared with enriched milk formula on growth, bone mass, and body composition. American Journal of Clinical Nutrition 84, 1357e1364. Lucas, A., 2005. Long-term programming effects of early nutrition. Implications for the preterm infant. Journal of Perinatology 25, S2eS6. Lucas, A., Morely, R., Cole, T., 1998. Randomised trial of early diet in preterm babies and later intelligent quotient. BMJ 317, 1481e1487. Lucas, A., Fewtrell, M.S., Morely, R., Singhal, A., Abbott, R.A., Isaacs, E., et al., 2001. Randomised trial of nutrientenriched formula versus standard formula for postdischarge preterm infants. Pediatrics 108, 703e711. Mactier, H., Weaver, L.T., 2005. Vitamin A and preterm infants: what we know, what we don’t know, and what we need to
know. Archives of Disease in Childhood Fetal Neonatal Ed 90, F103eF108. McCormick, F.M., Henderson, G., Fahey, T., McGuire, W., 2010. Multinutrient fortification of human breast milk for preterm infants following hospital discharge (review). The Cochrane Database Syst Rev (7), CD004866. Nikklasson, A., Engstrom, E., Hard, A., Albertsson Wikland, K., Strom, A., 2003. Growth in very preterm children: a longitudinal study. Pediatric Research 54, 899e905. Picauld, J., Decullier, E., Plan, O., Pidoux, O., Bin-Dorel, S., Van Egroo, L.D., Chapud, F., Claris, O., 2008. Growth and bone mineralisation in preterm infants fed preterm formula or standard term formula after discharge. Journal of Pediatrics 153, 616e621. Raghavendra, R., Georgieff, M.K., March 2009. Iron therapy for preterm infants. Clinics in Perinatology 36 (1), 27e42. Salle, B.L., Delvin, E., Claris, O., Hascoet, J.M., Levy, E., Dec 2007. Is it justifiable to administrate vitamin A, E and D for 6 months in the premature infant? Arch Pediatric 14 (12), 1408e1412. Tsang, R.C., Uauy, R., Koletzko, B., Zlotkin, S.H., 2005. Nutrition of the Preterm Infant: Scientific Basis and Practical Guidelines, second ed. Digital Education Publishing, Cincinnati. Young, L., Morgan, J., McCormick, F.M., McGuire, W., 2012 Mar 14. Nutrient-enriched formula versus standard term formula for preterm infants following hospital discharge. Cochrane Database Syst Rev 3, CD004696.
Available online at www.sciencedirect.com