A Narrative Review of Strategies to Optimize Nutrition, Feeding, and Growth among Preterm-Born Infants: Implications for Practice

Preterm birth is the leading cause of neonatal and under-5 mortality globally, and healthcare-related burden and nutrition-related morbidities are unsustainable, particularly in resource-limited regions. Additionally, preterm infants are susceptible to multiple adverse outcomes including growth faltering, suboptimal neurodevelopment, and multisystemic morbidities. Maturation, healing, repair, and restoration to normalcy in preterm-born infants require optimizing nutrition; only then, prognosis, growth, neurodevelopment, and overall quality of life can improve. In this article, we discuss the various evidence-based feeding and nutritional strategies that can be applicable even in resource-limited settings, where resources and infrastructure for advanced neonatal care are limited. This article addresses nutrition, feeding strategies, and growth monitoring in the neonatal intensive care unit and at discharge to optimize nutrition, growth, and development.

State of the evidence from clinical trials on human milk fortification for preterm infants

Infants born preterm or low birth weight are at risk for morbidity, mortality and later neuroimpairment. Appropriate early post-natal growth is associated with better outcomes in-hospital and post-discharge. Therefore, nutritional strategies that support growth may improve the long-term health of this population. Mother's milk with donor milk as a supplement are preferred sources of nutrition for these infants but may not always support growth, especially amongst infants born of very low birth weight (<1500 g) and or those with a major morbidity. Systematic reviews of randomised controlled trials to date demonstrate that multi-nutrient fortification of human milk improves in-hospital growth of preterm infants although data on long-term neurodevelopment are lacking. Further, individualised approaches to fortification based on milk analysis or the infant's metabolic response may improve growth over standard fortification. The evidence is insufficient to inform the timing of introducing fortifier, routine fortification of feeds post-discharge or routine use of fortifiers made from human instead of bovine milk. Importantly, there is insufficient data to determine if these fortification practices improve relevant clinical or neurodevelopmental outcomes. In sum, there is an urgent need for well-designed clinical trials to assess potential benefits and risks of fortification practices and at what cost.

Using Nature to Nurture: Breast Milk Analysis and Fortification to Improve Growth and Neurodevelopmental Outcomes in Preterm Infants

Premature infants are born prior to a critical window of rapid placental nutrient transfer and fetal growth-particularly brain development-that occurs during the third trimester of pregnancy. Subsequently, a large proportion of preterm neonates experience extrauterine growth failure and associated neurodevelopmental impairments. Human milk (maternal or donor breast milk) is the recommended source of enteral nutrition for preterm infants, but requires additional fortification of macronutrient, micronutrient, and energy content to meet the nutritional demands of the preterm infant in attempts at replicating in utero nutrient accretion and growth rates. Traditional standardized fortification practices that add a fixed amount of multicomponent fortifier based on assumed breast milk composition do not take into account the considerable variations in breast milk content or individual neonatal metabolism. Emerging methods of individualized fortification-including targeted and adjusted fortification-show promise in improving postnatal growth and neurodevelopmental outcomes in preterm infants.

The role of breast milk fortifier in the post-discharge nutrition of preterm infants

Infants born prematurely are often discharged from hospital before 37 weeks post-menstrual age. While breastfeeding will meet all the nutritional requirements of full-term infants, these preterm infants may need enhanced levels of protein, minerals and possibly energy to ensure optimum growth, bone mineralisation and neurological development. To meet these additional nutrient needs in the neonatal unit, it is currently recommended that multinutrient breast milk fortifier is added to maternal breast milk. There may also be benefits in continuing to provide fortified milk after discharge, potentially including improved growth and preserving breastfeeding, and this is increasingly becoming a recognised practice in some neonatal units. This article presents the discussion and consensus of a multidisciplinary panel of neonatologists, neonatal dietitians, a GP and a neonatal outreach sister. The aim is to develop guidance on providing safe and effective nutritional supplementation for preterm infants after discharge in order to maintain optimal growth. This guidance is aimed at community healthcare staff and is based on the limited evidence available, using shared best practice and expertise.

Preterm's Nutrition from Hospital to Solid Foods: Are We Still Navigating by Sight?

As preterm birth rates are globally increasing, together with research on preterms’ peculiar needs, neonatologists are still facing the challenge of how to properly feed them. The need to strike a balance between excessive catch-up growth and extrauterine growth retardation, both leading to adverse outcomes, is made even more difficult by the broad range of preterms’ needs. Although mother’s fresh milk is undoubtedly the best nourishment, its availability during hospital stay is often lower than recommended, and its fortification at discharge is still an open issue. Formula milks are available as an alternative to breast milk. However, choosing the right formula requires a thorough evaluation of the infant’s perinatal history and targets. Last but not least, adequate timing and initiation of weaning in premature babies are still a poorly explored matter. This narrative review aims at evaluating the multitude of issues to consider when feeding preterms in the three stages of their first life: in-hospital care, discharge, and, eventually, weaning. Given the current absence of internationally shared guidelines, understanding the potential pitfalls of preterms’ nutrition could help us trace the right path for the right preterm.

Comparison of Types of Breast Milk Fortification at Discharge from the Neonatal Intensive Care Unit and Breast Milk Feeding Rates and Growth at 4 Months Corrected Age

Background: Effects of breast milk (BM) enhancement on long-term BM feeding in preterm infants discharged from the neonatal intensive care unit (NICU) have not been examined previously. This study compares any BM feeding rates at 4 months corrected age (CA) in preterm infants discharged from the NICU on BM enhancement by fortification of expressed BM with infant formula additives (BM-F) versus BM supplemented with infant formula feeds (BM-S). Subjects and Methods: We compared infants born between January 1, 2013, and December 31, 2017, with gestational age <32 weeks or birth weight <1500 g, discharged home on BM-F or BM-S from two NICUs and followed at 4 months CA. Multivariate logistic regression with propensity scoring estimated the adjusted associations between nutrition at discharge and any BM feeding at 4 months CA. Results: Two hundred eighty-five infants were followed at 4 months CA. Infants discharged on BM-F were more likely to have mothers with multiple gestation, private insurance and not Caucasian, initiate feeds of human milk, be discharged from NICU-1, and receive any BM at 4 months CA (p < 0.03). No significant difference in growth parameters <10th percentile at 4 months CA was observed between the two groups. After adjusting for confounding factors, discharge from the NICU on BM-F was significantly associated with BM feeding at 4 months CA (odds ratio: 3.89, 95% confidence interval 1.66-9.14, p = 0.002). Conclusion: In this observational study, preterm infants receiving BM fortified with formula powder additives at discharge from the NICU had better BM feeding outcomes without poor growth at 4 months CA relative to those infants receiving BM supplemented with infant formula feeds.

VEP estimation of visual acuity: a systematic review

Purpose

Visual evoked potentials (VEPs) can be used to measure visual resolution via a spatial frequency (SF) limit as an objective estimate of visual acuity. The aim of this systematic review is to collate descriptions of the VEP SF limit in humans, healthy and disordered, and to assess how accurately and precisely VEP SF limits reflect visual acuity.

Methods

The protocol methodology followed the PRISMA statement. Multiple databases were searched using “VEP” and “acuity” and associated terms, plus hand search: titles, abstracts or full text were reviewed for eligibility. Data extracted included VEP SF limits, stimulus protocols, VEP recording and analysis techniques and correspondence with behavioural acuity for normally sighted healthy adults, typically developing infants and children, healthy adults with artificially degraded vision and patients with ophthalmic or neurological conditions.

Results

A total of 155 studies are included. Commonly used stimulus, recording and analysis techniques are summarised. Average healthy adult VEP SF limits vary from 15 to 40 cpd, depend on stimulus, recording and analysis techniques and are often, but not always, poorer than behavioural acuity measured either psychophysically with an identical stimulus or with a clinical acuity test. The difference between VEP SF limit and behavioural acuity is variable and strongly dependent on the VEP stimulus and choice of acuity test. VEP SF limits mature rapidly, from 1.5 to 9 cpd by the end of the first month of life to 12–20 cpd by 8–12 months, with slower improvement to 20–40 cpd by 3–5 years. VEP SF limits are much better than behavioural thresholds in the youngest, typically developing infants. This difference lessens with age and reaches equivalence between 1 and 2 years; from around 3–5 years, behavioural acuity is better than the VEP SF limit, as for adults. Healthy, artificially blurred adults had slightly better behavioural acuity than VEP SF limits across a wide range of acuities, while adults with heterogeneous ophthalmic or neurological pathologies causing reduced acuity showed a much wider and less consistent relationship. For refractive error, ocular media opacity or pathology primarily affecting the retina, VEP SF limits and behavioural acuity had a fairly consistent relationship across a wide range of acuity. This relationship was much less consistent or close for primarily macular, optic nerve or neurological conditions such as amblyopia. VEP SF limits were almost always normal in patients with non-organic visual acuity loss.

Conclusions

The VEP SF limit has great utility as an objective acuity estimator, especially in pre-verbal children or patients of any age with motor or learning impairments which prevent reliable measurement of behavioural acuity. Its diagnostic power depends heavily on adequate, age-stratified, reference data, age-stratified empirical calibration with behavioural acuity, and interpretation in the light of other electrophysiological and clinical findings. Future developments could encompass faster, more objective and robust techniques such as real-time, adaptive control.

Registration

International prospective register of systematic reviews PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), registration number CRD42018085666.

Fortification of Human Milk for Preterm Infants: Update and Recommendations of the European Milk Bank Association (EMBA) Working Group on Human Milk Fortification

Evidence indicates that human milk (HM) is the best form of nutrition uniquely suited not only to term but also to preterm infants conferring health benefits in both the short and long-term. However, HM does not provide sufficient nutrition for the very low birth weight (VLBW) infant when fed at the usual feeding volumes leading to slow growth with the risk of neurocognitive impairment and other poor health outcomes such as retinopathy and bronchopulmonary dysplasia. HM should be supplemented (fortified) with the nutrients in short supply, particularly with protein, calcium, and phosphate to meet the high requirements of this group of babies. In this paper the European Milk Bank Association (EMBA) Working Group on HM Fortification discusses the existing evidence in this field, gives an overview of different fortification approaches and definitions, outlines the gaps in knowledge and gives recommendations for practice and suggestions for future research. EMBA recognizes that "Standard Fortification," which is currently the most utilized regimen in neonatal intensive care units, still falls short in supplying sufficient protein for some VLBW infants. EMBA encourages the use of "Individualized Fortification" to optimize nutrient intake. "Adjustable Fortification" and "Targeted Fortification" are 2 methods of individualized fortification. The quality and source of human milk fortifiers constitute another important topic. There is work looking at human milk derived fortifiers, but it is still too early to draw precise conclusions about their use. The pros and cons are discussed in this Commentary in addition to the evidence around use of fortifiers post discharge.

ABM Clinical Protocol #12: Transitioning the Breastfeeding Preterm Infant from the Neonatal Intensive Care Unit to Home, Revised 2018

A central goal of the Academy of Breastfeeding Medicine is the development of clinical protocols, free from commercial interest or influence, for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Neurodevelopmental Outcomes of Preterm Infants Fed Human Milk: A Systematic Review

The neurodevelopmental benefits of breast milk feedings for preterm infants have been controversial. However, the effect on preterm infant neurodevelopment is sustained into childhood. The effects of breast milk feeding during the neonatal period and the duration of breastfeeding display effects on cognition into adolescence. The volume of breast milk received is a key factor in these effects. Additionally, emerging studies support the effects of human milk on structural brain development, such as increased white matter development and increased cortical thickness. The components of breast milk thought to mediate improved cognitive outcomes include long-chain polyunsaturated fatty acids and human milk oligosaccharides.

Working group reports: evaluation of the evidence to support practice guidelines for nutritional care of preterm infants-the Pre-B Project

The "Evaluation of the Evidence to Support Practice Guidelines for the Nutritional Care of Preterm Infants: The Pre-B Project" is the first phase in a process to present the current state of knowledge and to support the development of evidence-informed guidance for the nutritional care of preterm and high-risk newborn infants. The future systematic reviews that will ultimately provide the underpinning for guideline development will be conducted by the Academy of Nutrition and Dietetics' Evidence Analysis Library (EAL). To accomplish the objectives of this first phase, the Pre-B Project organizers established 4 working groups (WGs) to address the following themes: 1) nutrient specifications for preterm infants, 2) clinical and practical issues in enteral feeding of preterm infants, 3) gastrointestinal and surgical issues, and 4) current standards of infant feeding. Each WG was asked to 1) develop a series of topics relevant to their respective themes, 2) identify questions for which there is sufficient evidence to support a systematic review process conducted by the EAL, and 3) develop a research agenda to address priority gaps in our understanding of the role of nutrition in health and development of preterm/neonatal intensive care unit infants. This article is a summary of the reports from the 4 Pre-B WGs.

Managing the Human-Milk-Fed, Preterm, VLBW Infant at NICU Discharge

Preterm, very-low-birth-weight (VLBW) infants are at high nutritional risk because of poor nutrient stores at birth, digestive and neurodevelopmental immaturity, and increased risk of medical and surgical complications. Human milk (HM) is the preferred feeding for nearly all newborns. It is easily digested, well absorbed, and decreases the risk of infection. To meet the nutritional needs of small babies, however, HM requires fortification. HM fortification is the accepted norm during neonatal intensive care unit (NICU) hospitalization. This article reviews how to manage the human-milk-fed preterm VLBW infant at NICU discharge. Recent evidence suggests that HM alone after discharge may not replenish nutrient deficits accumulated during the hospital stay or sustain growth in the immediate follow-up period. Practitioners are challenged with devising nutritionally adequate diets that are practical and sustainable while preserving the HM supply and protecting the breastfeeding experience. We will review the available science; reveal pitfalls in common practices, including “the sprinkles dilemma”; and present several options for regimens that meet nutritional goals.

Post-discharge nutrition and the VLBW infant: To supplement or not supplement?: a review of the current evidence

Due to advancements in neonatology, the survival of very-low-birth-weight infants, especially extremely low-birth-weight infants continues to rise. The goal of nutrition in these preterm infants is to match the intrauterine growth curves of the normally growing fetus. Despite this recommendation from the American Academy of Pediatrics Committee on Nutrition, neonatologists struggle daily to meet this goal, and as a result, postnatal growth failure and restriction are common. This article reviews post-discharge nutrition in the VLBW population, examining different types of post-discharge nutrition, current evidence, and future and remaining questions. In addition, recommendations are provided for post-discharge nutrition in this population.

Post-discharge nutrition of the breastfed preterm infant

Provision of mother's own milk is the optimal way to nourish infants, including the preterm infant. The importance of mother's own milk during initial hospitalization to improve feeding tolerance, reduce serious infection and necrotizing enterocolitis is well appreciated. As a result, there has been a culture shift in neonatology such that breastfeeding is now encouraged and the majority of mothers of preterm infants attempt to express breastmilk. While more can be done during the hospital stay, nutrient intakes and growth are monitored and lactation support is provided. After hospital discharge, however, nutrient intakes and growth are frequently not monitored in a coordinated fashion and lactation support is often inaccessible. Few data are available to guide the clinician on the best approach to supporting the breastfed infant after discharge and expert guidance is frequently non-existent. This review provides evidence for a 'proactive' rather than a 'reactive' approach to supporting the breastfed preterm infant after discharge in terms of breastfeeding promotion, resolving acquired nutrient deficits, normalizing feeding and promoting optimal growth.

Multinutrient fortification of human breast milk for preterm infants following hospital discharge

BACKGROUND

Preterm infants are usually growth restricted at hospital discharge. Feeding preterm infants after hospital discharge with multinutrient fortified breast milk rather than unfortified breast milk may facilitate more rapid catch-up growth and improve neurodevelopmental outcomes.

OBJECTIVES

To determine the effect of feeding preterm infants following hospital discharge with multinutrient fortified human breast milk versus unfortified breast milk on growth and development.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included electronic searches of the Cochrane Central Register of Controlled Trials Register (CENTRAL, The Cochrane Library, 2012, Issue 3), MEDLINE, EMBASE and CINAHL (until August 2012), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared feeding preterm infants following hospital discharge with multinutrient fortified breast milk compared with unfortified human breast milk.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors and synthesis of data using risk ratio, risk difference and mean difference.

MAIN RESULTS

We identified two small trials involving a total of 246 infants. These did not provide evidence that multinutrient fortification of breast milk for three to four months after hospital discharge affected rates of growth during infancy. One trial assessed infants at 18 months corrected age and did not find any statistically significant effects on neurodevelopmental outcomes.

AUTHORS' CONCLUSIONS

The limited available data do not provide convincing evidence that feeding preterm infants with multinutrient fortified breast milk compared with unfortified breast milk following hospital discharge affects important outcomes including growth rates during infancy. There are no data on long-term growth. Since fortifying breast milk for infants fed directly from the breast is logistically difficult and has the potential to interfere with breast feeding, it is important to determine if mothers would support further trials of this intervention.