Individualized Human Milk Fortification to Improve the Growth of Hospitalized Preterm Infants

Using a new human milk fortifier to optimize human milk feeding among very preterm and/or very low birth weight infants: a multicenter study in China

BACKGROUND

Human milk fortifier (HMF) composition has been optimized recently. But clinical evidence of its safety and efficacy is limited in Chinese population. The aim of this study was to evaluate effects of a new HMF in growth, nutritional status, feeding intolerance, and major morbidities among very preterm (VPT) or very low birth weight (VLBW) infants in China.

METHODS

VPT/VLBW infants admitted from March 2020 to April 2021 were prospectively included in the experimental (new HMF, nHMF) group, who received a new powdered HMF as a breast milk feeding supplement during hospitalization. Infants in the control group (cHMF) admitted from January 2018 to December 2019, were retrospective included, and matched with nHMF group infants for gestational age and birth weight. They received other kinds of commercially available HMFs. Weight gain velocity, concentrations of nutritional biomarkers, incidence of major morbidities, and measures of feeding intolerance were compared between the two groups.

RESULTS

Demographic and clinical characteristics of infants in nHMF and cHMF groups were comparable. Weight gain velocity had no significant difference between the nHMF (14.0 ± 3.5 g/kg/d) and the cHMF group (14.2 ± 3.8 g/kg/d; P = 0.46). Incidence of morbidities, including necrotizing enterocolitis, bronchopulmonary dysplasia, retinopathy of prematurity, culture-confirmed sepsis, and feeding intolerance during hospitalization between nHMF and cHMF, were similar (all P-values > 0.05). The time to achieve full enteral feeding [13.5 (10, 21) days] in the nHMF group was significantly shorter than that in the cHMF group [17 (12, 23) days, HR = 0.67, 95%CI: 0.49, 0.92; P = 0.01]. Compared with cHMF group, the decrease of blood urea nitrogen level over time in nHMF group was smaller (β = 0.6, 95%CI:0.1, 1.0; P = 0.01).

CONCLUSIONS

The new HMF can promote growth of preterm infants effectively without increasing the incidence of major morbidity and feeding intolerance. It can be used feasible in Chinese VPT/VLBW infants.

TRIAL REGISTRATION

This study was registered on ClinicalTrials.gov (NCT04283799).

Human Milk Fortification for Very Preterm Infants: Toward Optimal Nutrient Delivery, Neonatal Intensive Care Unit Growth, and Long-Term Outcomes

Human milk is the preferred diet for very preterm infants due to short-term and long-term benefits for health and neurodevelopment. Fortification of human milk is required to deliver sufficient nutrients to attain recommended growth targets during the neonatal hospitalization. Intrinsic variability in human milk composition poses a challenge in clinical practice because some infants fail to meet recommended nutrient intakes even with existing approaches of standard (fixed-dose) and adjustable fortification. Individually targeted fortification is an emerging strategy to minimize nutrition delivery gaps through application of point-of-care human milk analysis and has potential to improve growth and related outcomes.

Individualized Fortification Based on Measured Macronutrient Content of Human Milk Improves Growth and Body Composition in Infants Born Less than 33 Weeks: A Mixed-Cohort Study

The optimal method for human milk (HM) fortification has not yet been determined. This study assessed whether fortification relying on measured HM macronutrient content (Miris AB analyzer, Upsala, Sweden) composition is superior to fortification based on assumed HM macronutrient content, to optimize the nutrition support, growth, and body composition in infants born at <33 weeks' gestation. In a mixed-cohort study, 57 infants fed fortified HM based on its measured content were compared with 58 infants fed fortified HM based on its assumed content, for a median of 28 and 23 exposure days, respectively. The ESPGHAN 2010 guidelines for preterm enteral nutrition were followed. Growth assessment was based on body weight, length, and head circumference Δ z-scores, and the respective growth velocities until discharge. Body composition was assessed using air displacement plethysmography. Fortification based on measured HM content provided significantly higher energy, fat, and carbohydrate intakes, although with a lower protein intake in infants weighing ≥ 1 kg and lower protein-to-energy ratio in infants weighing < 1 kg. Infants fed fortified HM based on its measured content were discharged with significantly better weight gain, length, and head growth. These infants had significantly lower adiposity and greater lean mass near term-equivalent age, despite receiving higher in-hospital energy and fat intakes, with a mean fat intake higher than the maximum recommended and a median protein-to-energy ratio intake (in infants weighing < 1 kg) lower than the minimum recommended.

Effect of Targeted vs. Standard Fortification of Breast Milk on Growth and Development of Preterm Infants (≤32 Weeks): Results from an Interrupted Randomized Controlled Trial

Human milk is recommended for very low birth weight infants. Their nutritional needs are high, and the fortification of human milk is a standard procedure to optimize growth. Targeted fortification accounts for the variability in human milk composition. It has been a promising alternative to standard fixed-dose fortification, potentially improving short-term growth. In this trial, preterm infants (≤32 weeks of gestation) were randomized to receive human milk after standard fortification (HMF, Nutricia) or tailored fortification with modular components of proteins (Bebilon Bialko, Nutricia), carbohydrates (Polycal, Nutricia), and lipids (Calogen, Nutricia). The intervention started when preterms reached 80 mL/kg/day enteral feeds. Of the target number of 220 newborns, 39 were randomized. The trial was interrupted due to serious intolerance in five cases. There was no significant difference in velocity of weight gain during the supplementation period (primary outcome) in the tailored vs. standard fortification group: 27.01 ± 10.19 g/d vs. 25.84 ± 13.45 g/d, p = 0.0776. Length and head circumference were not significantly different between the groups. We found the feasibility of targeted fortification to be limited in neonatal intensive care unit practice. The trial was registered at clinicaltrials.gov NCT:03775785.

Preterm birth and human milk proteome: are we ready for individualized fortification?

PURPOSE OF REVIEW

Preterm birth is one of the most pressing clinical problems in obstetrics and neonatology worldwide. One of the most sophisticated components of human milk is the proteome and a better understanding of it can lead to precision guides for feeding preterm infants. In this review, we will examine recent research focused on the human milk proteome and individualized protein fortification of human milk.

RECENT FINDINGS

In both preterm and term birth, the protein content in mother's own milk dropped rapidly in the early postnatal period. Preterm milk had a higher protein content and contained different protein and endogenous peptide compositions compared with term milk. The peptides in gastrointestinal fluids of preterm infants still need further investigation. Individualized fortification is more superior to standard fortification, but it only focuses on the total protein amount. There is no data concerning the composition and posttranslational modifications of proteins and endogenous peptides with fortification and their longterm effects.

SUMMARY

Comprehensive identification and characterization of the human milk proteome have led to the targeted breast milk fortification theory of preterm infant feeding and has also been enriched by clinical trials. However, to achieve fortification of key proteins and/or endogenous peptides, as standard clinical practice, requires additional studies. Future research should explore the long-term effect of protein fortification and pay more attention to quality rather than quantity in relation to infant body composition and growth outcomes.

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.

Corrected fortification approach improves the protein and energy content of preterm human milk compared with standard fixed-dose fortification

OBJECTIVE

To evaluate whether a pragmatic corrected fortification (CF) model achieves recommended target protein and calorie content of human milk (HM) for preterm infants when compared with standard fixed-dose fortification (SF).

DESIGN

In this prospective non-interventional study, we enrolled mothers of infants with birth weight ≤1500 g fed exclusive HM. Infants with chromosomal or intestinal disorders were excluded. A total of 405 HM samples from 29 mothers and 45 donor milk samples were analysed for macronutrient content using a real-time HM analyser. A stepwise CF model was derived based on published data on HM calorie and protein content corrected for lactation stage and milk type. We applied both models to the measured protein and calorie content for all HM samples and compared the proportion of samples achieving target nutrient requirement in each group.

RESULTS

Target protein and calorie content of feed was achieved in 68% of HM samples with CF, compared with 5% samples with SF model (p<0.0001). For mother's own milk, none of the samples met the target macronutrient range with SF fortification during later lactation periods (≥week 5). With SF, over 40% of infants had poor growth (decline in weight z-score ≥0.8 SD) by 8 weeks. The final feed osmolality was acceptable for all fortification steps of the CF model.

CONCLUSION

The proposed CF model significantly improved the final protein and calorie content of HM with acceptable osmolality. It provides a proactive option to improve nutrient intake in premature infants.

Preterm infant nutrition and growth with a human milk diet

Human milk is the preferred enteral diet for preterm infants. It provides macronutrients, micronutrients, and bioactive factors that support physical growth and neurodevelopment. Challenges of the human milk diet include the variability in its composition and a need for fortification to mirror placental nutrient delivery and prevent extrauterine growth restriction. Various strategies exist to attain target nutrient provision and optimize growth, including leveraging new technology for point-of-care human milk analysis. When maternal milk is unavailable or in short supply, pasteurized donor human milk is the preferred alternative. Infants fed donor milk may have slower weight gain than those fed exclusively maternal milk or formula, whereas infants fed fortified maternal milk have similar weight gain to preterm formula-fed infants. Future directions include more rigorous characterization of the variation in human milk, further investigation of the clinical benefits of non-nutrient bioactive factors in milk, and novel approaches to optimize fortification.

Customized Human Milk Fortification Based on Measured Human Milk Composition to Improve the Quality of Growth in Very Preterm Infants: A Mixed-Cohort Study Protocol

Adequate nutrition of very preterm infants comprises fortification of human milk (HM), which helps to improve their nutrition and health. Standard HM fortification involves a fixed dose of a multi-nutrient HM fortifier, regardless of the composition of HM. This fortification method requires regular measurements of HM composition and has been suggested to be a more accurate fortification method. This observational study protocol is designed to assess whether the target HM fortification method (contemporary cohort) improves the energy and macronutrient intakes and the quality of growth of very preterm infants, compared with the previously used standard HM fortification (historical cohorts). In the contemporary cohort, a HM multi-nutrient fortifier and modular supplements of protein and fat are used for HM fortification, and the enteral nutrition recommendations of the European Society for Paediatric Gastroenterology Hepatology and Nutrition for preterm infants will be considered. For both cohorts, the composition of HM is assessed using the Miris Human Milk analyzer (Uppsala, Sweden). The quality of growth will be assessed by in-hospital weight, length, and head circumference growth velocities and a single measurement of adiposity (fat mass percentage and fat mass index) performed just after discharge, using the air displacement plethysmography method (Pea Pod, Cosmed, Italy). ClinicalTrials.gov registration number: NCT04400396.

Methionine promotes crop milk protein synthesis through the JAK2-STAT5 signaling during lactation of domestic pigeons (Columba livia)

Crop milk is the sole source of nutrition that sustains young pigeons (squabs) throughout growth and development. Protein accounts for approximately 55% of the nutrients in crop milk; however, its regulation mechanism remains unclear. In our study, three experiments were conducted to investigate the possible underlying mechanism of crop milk protein synthesis and nutritional interventions. Isobaric tagging for relative and absolute quantification (iTRAQ) analysis found that the Janus activated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway was significantly up-regulated in breeding pigeons during lactation compared to non-breeding pigeons. Moreover, the serum prolactin (PRL) levels increased, and the protein expression of the PRL receptor (PRLR)/JAK2/STAT5 pathway was significantly up-regulated during lactation. The serum PRL, the PRLR/JAK2/STAT5 pathway, the crop milk protein synthesis, and the squab growth performance were inhibited by bromocriptine mesylate injection, a PRL-specific inhibitor. In addition, dietary supplementation with 0.30% dl-methionine or dl-methionine-dl-methionine (especially 0.30% dl-methionine-dl-methionine), significantly increased serum PRL levels and PRLR/JAK2/STAT5 activity, and improved the crop milk protein synthesis. In conclusion, our results demonstrated that the PRL-induced PRLR/JAK2/STAT5 signaling pathway plays a vital regulatory role in crop milk protein synthesis, and 0.30% dl-methionine-dl-methionine is superior to dl-methionine in promoting crop milk protein synthesis.

Individualized versus standard diet fortification for growth and development in preterm infants receiving human milk

BACKGROUND

Human milk as compared to formula reduces morbidity in preterm infants but requires fortification to meet their nutritional needs and to reduce the risk of extrauterine growth failure. Standard fortification methods are not individualized to the infant and assume that breast milk is uniform in nutritional content. Strategies for individualizing fortification are available; however it is not known whether these are safe, or if they improve outcomes in preterm infants.

OBJECTIVES

To determine whether individualizing fortification of breast milk feeds in response to infant blood urea nitrogen (adjustable fortification) or to breast milk macronutrient content as measured with a milk analyzer (targeted fortification) reduces mortality and morbidity and promotes growth and development compared to standard, non-individualized fortification for preterm infants receiving human milk at < 37 weeks' gestation or at birth weight < 2500 grams.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 9), in the Cochrane Library; Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions(R); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), on September 20, 2019. We also searched clinical trials databases and the reference lists of retrieved articles for pertinent randomized controlled trials (RCTs) and quasi-randomized trials.

SELECTION CRITERIA

We considered randomized, quasi-randomized, and cluster-randomized controlled trials of preterm infants fed exclusively breast milk that compared a standard non-individualized fortification strategy to individualized fortification using a targeted or adjustable strategy. We considered studies that examined any use of fortification in eligible infants for a minimum duration of two weeks, initiated at any time during enteral feeding, and providing any regimen of human milk feeding.

DATA COLLECTION AND ANALYSIS

Data were collected using the standard methods of Cochrane Neonatal. Two review authors evaluated the quality of the studies and extracted data. We reported analyses of continuous data using mean differences (MDs), and dichotomous data using risk ratios (RRs). We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

Data were extracted from seven RCTs, resulting in eight publications (521 total participants were enrolled among these studies), with duration of study interventions ranging from two to seven weeks. As compared to standard non-individualized fortification, individualized (targeted or adjustable) fortification of enteral feeds probably increased weight gain during the intervention (typical mean difference [MD] 1.88 g/kg/d, 95% confidence interval [CI] 1.26 to 2.50; 6 studies, 345 participants), may have increased length gain during the intervention (typical MD 0.43 mm/d, 95% CI 0.32 to 0.53; 5 studies, 242 participants), and may have increased head circumference gain during the intervention (typical MD 0.14 mm/d, 95% CI 0.06 to 0.23; 5 studies, 242 participants). Compared to standard non-individualized fortification, targeted fortification probably increased weight gain during the intervention (typical MD 1.87 g/kg/d, 95% CI 1.15 to 2.58; 4 studies, 269 participants) and may have increased length gain during the intervention (typical MD 0.45 mm/d, 95% CI 0.32 to 0.57; 3 studies, 166 participants). Adjustable fortification probably increased weight gain during the intervention (typical MD 2.86 g/kg/d, 95% CI 1.69 to 4.03; 3 studies, 96 participants), probably increased gain in length during the intervention (typical MD 0.54 mm/d, 95% CI 0.38 to 0.7; 3 studies, 96 participants), and increased gain in head circumference during the intervention (typical MD 0.36 mm/d, 95% CI 0.21 to 0.5; 3 studies, 96 participants). We are uncertain whether there are differences between individualized versus standard fortification strategies in the incidence of in-hospital mortality, bronchopulmonary dysplasia, necrotizing enterocolitis, culture-proven late-onset bacterial sepsis, retinopathy of prematurity, osteopenia, length of hospital stay, or post-hospital discharge growth. No study reported severe neurodevelopmental disability as an outcome. One study that was published after our literature search was completed is awaiting classification.

AUTHORS' CONCLUSIONS

We found moderate- to low-certainty evidence suggesting that individualized (either targeted or adjustable) fortification of enteral feeds in very low birth weight infants increases growth velocity of weight, length, and head circumference during the intervention compared with standard non-individualized fortification. Evidence showing important in-hospital and post-discharge clinical outcomes was sparse and of very low certainty, precluding inferences regarding safety or clinical benefits beyond short-term growth.

Comparison of different protein concentrations of human milk fortifier for promoting growth and neurological development in preterm infants

BACKGROUND

Human milk alone may provide inadequate amounts of protein to meet the growth requirements of preterm infants because of restrictions in the amount of fluid they can tolerate. It has become common practice to feed preterm infants with breast milk fortified with protein and other nutrients but there is debate about the optimal concentration of protein in commercially available fortifiers.

OBJECTIVES

To compare the effects of different protein concentrations in human milk fortifier, fed to preterm infants, on growth and neurodevelopment.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search CENTRAL (2019, Issue 8), Ovid MEDLINE and CINAHL on 15 August 2019. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We included all published and unpublished randomised, quasi-randomised and cluster-randomised trials comparing two different concentrations of protein in human milk fortifier. We included preterm infants (less than 37 weeks' gestational age). Participants may have been exclusively fed human milk or have been supplemented with formula. The concentration of protein was classified as low (< 1g protein/100 mL expressed breast milk (EBM)), moderate (≥ 1g to < 1.4g protein/100 mL EBM) or high (≥ 1.4g protein/100 mL EBM). We excluded trials that compared two protein concentrations that fell within the same category.

DATA COLLECTION AND ANALYSIS

We undertook data collection and analyses using the standard methods of Cochrane Neonatal. Two review authors independently evaluated trials. Primary outcomes included growth, neurodevelopmental outcome and mortality. Data were synthesised using risk ratios (RR), risk differences and mean differences (MD), with 95% confidence intervals (CI). We used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We identified nine trials involving 861 infants. There is one trial awaiting classification, and nine ongoing trials. The trials were mostly conducted in infants born < 32 weeks' gestational age or < 1500 g birthweight, or both. All used a fortifier derived from bovine milk. Two trials fed infants exclusively with mother's own milk, three trials gave supplementary feeds with donor human milk and four trials supplemented with preterm infant formula. Overall, trials were small but generally at low or unclear risk of bias. High versus moderate protein concentration of human milk fortifier There was moderate certainty evidence that a high protein concentration likely increased in-hospital weight gain compared to moderate concentration of human milk fortifier (MD 0.66 g/kg/day, 95% CI 0.51 to 0.82; trials = 6, participants = 606). The evidence was very uncertain about the effect of high versus moderate protein concentration on length gain (MD 0.01 cm/week, 95% CI -0.01 to 0.03; trials = 5, participants = 547; very low certainty evidence) and head circumference gain (MD 0.00 cm/week, 95% CI -0.01 to 0.02; trials = 5, participants = 549; very low certainty evidence). Only one trial reported neonatal mortality, with no deaths in either group (participants = 45). Moderate versus low protein concentration of human milk fortifier A moderate versus low protein concentration fortifier may increase weight gain (MD 2.08 g/kg/day, 95% CI 0.38 to 3.77; trials = 2, participants = 176; very low certainty evidence) with little to no effect on head circumference gain (MD 0.13 cm/week, 95% CI 0.00 to 0.26; I² = 85%; trials = 3, participants = 217; very low certainty evidence), but the evidence is very uncertain. There was low certainty evidence that a moderate protein concentration may increase length gain (MD 0.09 cm/week, 95% CI 0.05 to 0.14; trials = 3, participants = 217). Only one trial reported mortality and found no difference between groups (RR 0.48, 95% CI 0.05 to 5.17; participants = 112). No trials reported long term growth or neurodevelopmental outcomes including cerebral palsy and developmental delay.

AUTHORS' CONCLUSIONS

Feeding preterm infants with a human milk fortifier containing high amounts of protein (≥ 1.4g/100 mL EBM) compared with a fortifier containing moderate protein concentration (≥ 1 g to < 1.4 g/100 mL EBM) results in small increases in weight gain during the neonatal admission. There may also be small increases in weight and length gain when infants are fed a fortifier containing moderate versus low protein concentration (< 1 g protein/100 mL EBM). The certainty of this evidence is very low to moderate; therefore, results may change when the findings of ongoing studies are available. There is insufficient evidence to assess the impact of protein concentration on adverse effects or long term outcomes such as neurodevelopment. Further trials are needed to determine whether modest increases in weight gain observed with higher protein concentration fortifiers are associated with benefits or harms to long term growth and neurodevelopment.

Targeted Breast Milk Fortification for Very Low Birth Weight (VLBW) Infants: Nutritional Intake, Growth Outcome and Body Composition

Despite improvements in nutritional management, preterm infants continue to face high rates of postnatal growth restriction. Because variability in breast milk composition may result in protein and energy deficits, targeted fortification has been advocated. We conducted an interventional study to compare body composition and growth outcomes of very low birth weight infants fed targeted protein-fortified human milk (HM) with those fed standard fortified HM. If mother’s own milk was not available, donor milk was used. Weekly analysis of HM with mid-infrared spectroscopy was conducted and additional protein was added to the fortified HM to ensure a protein intake of 4 g/kg/day. Weekly anthropometric measurements were done. Prior to discharge or at 37 weeks, corrected age skinfold thickness (SFT) measurements as well as body composition measurement using air displacement plethysmography were done. Among 36 preterm infants enrolled, those in the targeted group (n = 17) received more protein and had a larger flank SFT at study end than those in the standard group (n = 19). A pilot post-hoc analysis of subjects having at least 30 intervention days showed a 3% higher fat-free mass in the targeted group. Use of a targeted fortification strategy resulted in a higher protein intake and fat-free mass among those receiving longer intervention.