Early full enteral feeding for preterm or low birth weight infants

Early and exclusive enteral nutrition in infants born very preterm

OBJECTIVE

To characterise the effects of early and exclusive enteral nutrition with either maternal or donor milk in infants born very preterm (280/7-326/7 weeks of gestation).

DESIGN

Parallel-group, unmasked randomised controlled trial.

SETTING

Regional, tertiary neonatal intensive care unit.

PARTICIPANTS

102 infants born very preterm between 2021 and 2022 (51 in each group).

INTERVENTION

Infants randomised to the intervention group received 60-80 mL/kg/day within the first 36 hours after birth. Infants randomised to the control group received 20-30 mL/kg/day (standard trophic feeding volumes).

MAIN OUTCOME MEASURES

The primary outcome was the number of full enteral feeding days (>150 mL/kg/day) in the first 28 days after birth. Secondary outcomes included growth and body composition at the end of the first two postnatal weeks, and length of hospitalisation.

RESULTS

The mean birth weight was 1477 g (SD: 334). Half of the infants were male, and 44% were black. Early and exclusive enteral nutrition increased the number of full enteral feeding days (+2; 0-2 days; p=0.004), the fat-free mass-for-age z-scores at postnatal day 14 (+0.5; 0.1-1.0; p=0.02) and the length-for-age z-scores at the time of hospital discharge (+0.6; 0.2-1.0; p=0.002). Hospitalisation costs differed between groups (mean difference favouring the intervention group: -$28 754; -$647 to -$56 861; p=0.04).

CONCLUSIONS

In infants born very preterm, early and exclusive enteral nutrition increases the number of full enteral feeding days. This feeding practice may also improve fat-free mass accretion, increase length and reduce hospitalisation costs.

TRIAL REGISTRATION NUMBER

NCT04337710.

Early Feeding for the Prevention of Neonatal Hypoglycaemia: A Systematic Review and Meta-Analysis

BACKGROUND

Poor feeding, among other factors, predisposes neonates to hypoglycaemia. Early feeding is widely recommended to prevent hypoglycaemia in those at risk, but the effectiveness of this is uncertain. This review aimed to summarise and analyse the evidence on the effectiveness of early feeding for prevention of neonatal hypoglycaemia.

METHODS

Four databases and three clinical trial registries were searched from inception to May 24, 2023. Published and unpublished randomised controlled trials (RCTs), quasi-RCTs, cluster randomised trials, non-randomised studies of interventions, and observational studies with comparison groups were considered for inclusion with no language or publication date restrictions. We included studies of neonates who were fed early (within 60 min of birth or study defined) versus delayed. Study quality was assessed using the Cochrane Risk of Bias 1 tool or Effective Public Health Practice Project Quality Assessment tool. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. RevMan 5.4.1 or R was used to synthesise results in random-effects meta-analyses. This review was registered prospectively with PROSPERO (CRD42022378904).

RESULTS

A total of 175,392 participants were included across 19 studies, of which two were RCTs, 14 cohort studies, two cross-sectional studies, and one a case-control study. Most studies (13/19) were conducted in low- or lower-middle-income countries. Early feeding may be associated with reduced neonatal hypoglycaemia (four cohort studies, 744 infants, odds ratio [OR] 0.19 (95% CI: 0.10-0.35), p < 0.00001, I2 = 44%) and slightly reduced duration of initial hospital stay (one cohort study, 1,673 infants, mean difference: -0.20 days [95% CI: -0.31 to -0.09], p = 0.0003), but the evidence is very uncertain. One RCT found early feeding had little or no effect on the risk of neonatal mortality, but three cohort studies found early feeding may be associated with reduced risk (136,468 infants, OR 0.51 [95% CI: 0.37-0.72]; low certainty evidence; p <0.0001; I2 = 54%).

CONCLUSION

We found that early feeding may reduce the incidence of neonatal hypoglycaemia, but the evidence is very uncertain. Given its many other benefits, early feeding should continue to be recommended. This review was primarily funded by the Aotearoa Foundation and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health.

Dilemmas in establishing preterm enteral feeding: where do we start and how fast do we go?

Beginning and achieving full enteral nutrition is a key step in the care of preterm infants, particularly very low birth weight (VLBW) infants. As is true for many organ system-specific complications of prematurity, the gastrointestinal tract must complete in utero development ex utero while concurrently serving a physiologic role reserved for after completion of full term development. The preterm gut must assume the placental function of the interface between a source of energy, precursors for anabolism, and micronutrients, and the developing infant-through digestion and absorption of milk, instead of directly from the mother via the uteroplacental interface. The benefits of enteral nourishment in preterm infants are counterbalanced by gastrointestinal complications of prematurity: dysmotility leading to difficulty establishing and advancing feeds, and the risk of necrotizing enterocolitis (NEC). Concern for these complications can prolong the need for parenteral nutrition with an associated increase in risk for central line-associated bloodstream infection (CLABSI) and parenteral nutrition (PN)-associated cholestasis or liver disease (PNALD). Thus, a daily issue facing neonatologists caring for preterm infants is how to optimally begin, advance, and reach full enteral nutrition sufficient to satisfy the nutrient, energy, and fluid requirements of VLBW infants while minimizing risk. In this perspective, we provide an overview of the approaches and supporting data for starting and advancing enteral feeds in preterm infants, particularly very low birth weight infants, and we discuss the significant gaps in knowledge that accompany current approaches. This framework recognizes the dilemmas of preterm feeding initiation and advancement and identifies areas of opportunity for further investigation.

Combined Nutrition in Very-Low-Birth-Weight Preterm Infants in the Neonatal Intensive Care Unit

Background Adequate nutritional support is crucial for achieving optimal growth and development in very-low-birth-weight (VLBW) preterm infants. This study evaluated the efficacy of combined nutrition (CN) (parenteral plus enteral nutrition (EN)) as an alternative nutrition protocol for VLBW infants in the neonatal intensive care unit (NICU). Methods This retrospective cohort study collected clinical and growth data from the medical records of VLBW infants weighing between 1,000 and 1,500 grams in the NICU of the Hospital of Obstetrics and Gynecology "Dr. Víctor Manuel Espinosa de los Reyes Sánchez" of the Centro Médico Nacional "La Raza" Instituto Mexicano del Seguro Social, Mexico. Parenteral nutrition (PN) alone or CN (PN plus EN) was used for nutritional management. Statistical tests, such as Student's t-test, Mann-Whitney U test, and chi-square test as appropriate, were used to compare the clinical characteristics and growth data of the two groups, and relative risk was calculated to determine the probability of comorbidities according to feeding type. Statistical significance was set at p<0.05. Results The study included 90 VLBW infants, with 27 receiving PN alone and 63 receiving CN. No statistically significant differences were found concerning sex, age, or Apgar score. The CN group showed better weight gain with statistically significant differences at 28 days (p=0.002), with no increase in the relative risk of necrotizing enterocolitis (NEC) or other complications. Conclusions The CN protocol met the caloric and nutritional needs, without increasing morbidity and mortality. The protocol had a positive impact on weight gain and a shorter NICU stay and should be considered as a nutritional alternative for VLBW infants.

Association between Abnormal Antenatal Doppler Characteristics and Gastrointestinal Outcomes in Preterm Infants

Antenatal Doppler disturbances are associated with fetal hypoxia and may induce a brain-sparing vascular redistribution at the expense of splanchnic circulation, possibly predisposing to gut complications. We aimed to compare several gastrointestinal outcomes among very-low-birthweight (VLBW) preterm infants with different antenatal Doppler features. VLBW infants born between 2010-2022 were retrospectively included and stratified into the following clusters based on antenatal Doppler characteristics: normal Doppler (controls); absent or reversed end-diastolic flow in the umbilical artery (UA-AREDF) alone or also in the ductus venosus (UA+DV-AREDF); and abnormal Doppler with or without brain-sparing redistribution. The following outcomes were evaluated: time to reach full enteral feeds (FEF), feeding intolerance (FI), necrotizing enterocolitis (NEC), and spontaneous intestinal perforation (SIP). Overall, 570 infants were included. Infants born following UA+DV-AREDF had significantly higher FI, NEC, and SIP rates and achieved FEF later compared to controls. Increased FI prevalence and a longer time to FEF compared to controls were also observed among UA-AREDF infants and in the presence of brain-sparing redistribution, which also increased NEC rates. Antenatal Doppler abnormalities exacerbate the gastrointestinal risks of preterm infants. Detailed knowledge of Doppler features can aid in identifying those at highest risk of intestinal complications who may benefit from tailored enteral feeding management.

A potential pathogenic hypoxia-related gene HK2 in necrotizing enterocolitis (NEC) of newborns

Background

Necrotizing enterocolitis (NEC) is a disastrous gastrointestinal disease of newborns, and the mortality rate of infants with NEC is approximately 20%-30%. The exploration of pathogenic targets of NEC will be conducive to timely diagnosis of NEC.

Methods

The whole transcriptome RNA sequencing was performed on NEC samples to reveal the expression of lncRNAs, circRNAs, miRNAs and mRNAs. Using differential expression analysis, cross analysis, target prediction, enrichment analysis, the pathogenic ceRNA network and target was found.

Results

Preliminarily, 281 DEmRNAs, 21 DEmiRNAs, 253 DElncRNAs and 207 DEcircRNAs were identified in NEC samples compared with controls. After target prediction and cross analyses, a key ceRNA regulatory network was built including 2 lncRNAs, 4 circRNAs, 2 miRNAs and 20 mRNAs. These 20 mRNAs were significantly enriched in many carbohydrate metabolism related pathways. After cross analysis of hypoxia-, carbohydrate metabolism-related genes, and 20 core genes, one gene HK2 was finally obtained. Dendritic cells activated were significantly differentially infiltrated and negatively correlated with HK2 expression in NEC samples.

Conclusions

The promising pathogenic hypoxia-related gene HK2 has been firstly identified in NEC, which might also involve in the carbohydrate metabolism in NEC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03664-w.

Effectiveness of early enteral feeding on health outcomes in preterm infants: an overview of systematic reviews

Early enteral feeding is vital for the physical health of preterm infants. However, there is uncertainty regarding the effects of early enteral feeding on health outcomes in preterm infants. Hence, we aimed to synthesise evidence from systematic reviews (SRs) to evaluate the effects of early enteral feeding on health outcomes in preterm infants. We conducted a literature search in PubMed, Web of Science, Scopus, and the Cochrane Database of Systematic Reviews. SRs selection followed clear inclusion and exclusion criteria. Two reviewers reached a consensus for the inclusion of SRs. The certainty of evidence and the quality of reviews using the GRADE and AMSTAR tools, respectively. We included nine SRs in this review. The effectiveness of early enteral feeding on health outcomes in preterm infants is mainly divided into six primary outcomes: increase the weight gain, reduce the incidence of feed intolerance, shorten the duration of full enteral feeding, reduce the length of hospital stay, reduce the incidence of necrotizing enterocolitis, and decrease the mortality risk. The overall quality of the included SRs was high, whereas most of the evidence was of low or very low certainty. Our results show the impact of early enteral feeding on health outcomes in preterm infants. Although the currently available data indicate that early enteral feeding may improve the health outcomes of preterm infants, additional clinical observation and investigation are required to evaluate the long-term health outcomes of preterm infants who receive early enteral feeding.

Availability of donor milk improves enteral feeding but has limited effect on body growth of infants with very-low birthweight: Data from a historic cohort study

Compare with preterm formula, donor human milk (DM) is associated with a lower risk of mortality and morbidity in preterm infants. It is thus deemed superior to preterm formula as the sole diet or supplement to own mother's milk (OMM) for preterm infants, especially for those with very low birthweight (VLBW). This historic cohort study investigated the relationship between DM availability, and enteral feeding, body growth of VLBW infants by comparing two cohorts before and after the establishment of a human milk bank. A sub‐analysis was also conducted between small‐for‐gestational‐age (SGA) and non‐SGA infants in our cohorts. Our results showed that DM availability was associated with earlier initiation and faster advancement of enteral feeding, earlier attainment of full enteral feeding, and a higher proportion of OMM in enteral feeding. DM availability was also associated with earlier regain of birthweight, but not with better body growth. SGA and non‐SGA infants responded differently to DM availability with only the non‐SGA group showing improved enteral feeding associated with DM availability. The poor growth of VLBW infants with fortified DM warrants further investigations on better fortification strategies to further improve body growth. Studies are also needed on long‐term effects of DM feeding on the development of VLBW infants.

Compared with the infants before the introduction of donor human milk (DM), very low birthweight infants after that had improved enteral feeding process, shown as earlier enteral feeding introduction, faster advancement, and earlier attainment of full enteral feeding.

DM availability affects body growth to a limited extent, which calls for a better fortification strategy for DM‐fed infants.

The setup of a human donor milk bank increased the use of own mother's milk for enteral feeding.

Gestational Age-Related Associations between Early-Life Feeding Trajectories and Growth Outcomes at Term Equivalent Age in Very Preterm Infants

Establishing the different feeding trajectories based on daily enteral feeding data in preterm infants at different gestational ages (GAs), may help to identify the risks and extrauterine growth restriction (EUGR) outcomes associated with the adverse feeding pattern. In a single center, we retrospectively included 625 infants born at 23-30 weeks of gestation who survived to term-equivalent age (TEA) from 2009 to 2020. The infants were designated into three GA groups: 23-26, 27-28, and 29-30 weeks. The daily enteral feeding amounts in the first 56 postnatal days were analyzed to determine the feeding trajectories. The primary outcomes were EUGR in body weight and head circumference calculated, respectively, by the changes between birth and TEA. Clustering analysis identified two feeding trajectories, namely the improving and adverse patterns in each GA group. The adverse feeding pattern that occurred in 49%, 20%, and 17% of GA 23-26, 27-28, and 29-30 weeks, respectively, was differentiated from the improving feeding pattern as early as day 7 in infants at GA 23-26 and 27-28 weeks, in contrast to day 21 in infants at GA 29-30 weeks. The adverse feeding patterns were associated with sepsis, respiratory, and gastrointestinal morbidities at GA 23-26 weeks; sepsis, hemodynamic and gastrointestinal morbidities at GA 27-28 weeks; and preeclampsia, respiratory, and gastrointestinal morbidities at GA 29-30 weeks. Using the improving feeding group as a reference, the adverse feeding group showed significantly higher adjusted odds ratios of EUGR in body weight and head circumference in infants at GA 23-26 and 27-28 weeks. Identifying the early-life adverse feeding trajectories may help recognize the related EUGR outcomes of preterm infants in a GA-related manner.

Slow advancement of enteral feed volumes to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

Early enteral feeding practices are potentially modifiable risk factors for necrotising enterocolitis (NEC) in very preterm or very low birth weight (VLBW) infants. Observational studies suggest that conservative feeding regimens, including slowly advancing enteral feed volumes, reduce the risk of NEC. However, it is unclear whether slow feed advancement may delay establishment of full enteral feeding, and if it could be associated with infectious morbidities secondary to prolonged exposure to parenteral nutrition.

OBJECTIVES

To determine the effects of slow rates of enteral feed advancement on the risk of NEC, mortality, and other morbidities in very preterm or VLBW infants.

SEARCH METHODS

We searched CENTRAL (2020, Issue 10), Ovid MEDLINE (1946 to October 2020), Embase via Ovid (1974 to October 2020), Maternity and Infant Care database (MIDIRS) (1971 to October 2020), CINAHL (1982 to October 2020), and clinical trials databases and reference lists of retrieved articles for eligible trials.

SELECTION CRITERIA

We included randomised or quasi-randomised controlled trials that assessed effects of slow (up to 24 mL/kg/d) versus faster rates of advancement of enteral feed volumes on the risk of NEC in very preterm or VLBW infants.

DATA COLLECTION AND ANALYSIS

Two review authors separately evaluated trial risk of bias, extracted data, and synthesised effect estimates using risk ratio (RR), risk difference (RD), and mean difference. We used the GRADE approach to assess the certainty of evidence. Outcomes of interest were NEC, all-cause mortality, feed intolerance, and invasive infection.

MAIN RESULTS

We included 14 trials involving a total of 4033 infants (2804 infants participated in one large trial). None of the trials masked parents, caregivers, or investigators. Risk of bias was otherwise low. Most infants were stable very preterm or VLBW infants of birth weight appropriate for gestation. About one-third of all infants were extremely preterm or extremely low birth weight (ELBW), and about one-fifth were small for gestational age, growth-restricted, or compromised as indicated by absent or reversed end-diastolic flow velocity in the foetal umbilical artery. Trials typically defined slow advancement as daily increments of 15 to 24 mL/kg, and faster advancement as daily increments of 30 to 40 mL/kg. Meta-analyses showed that slow advancement of enteral feed volumes probably has little or no effect on the risk of NEC (RR 1.06, 95% confidence interval (CI) 0.83 to 1.37; RD 0.00, 95% CI -0.01 to 0.02; 14 trials, 4026 infants; moderate-certainty evidence) or all-cause mortality prior to hospital discharge (RR 1.13, 95% CI 0.91 to 1.39; RD 0.01, 95% CI -0.01 to 0.02; 13 trials, 3860 infants; moderate-certainty evidence). Meta-analyses suggested that slow advancement may slightly increase feed intolerance (RR 1.18, 95% CI 0.95 to 1.46; RD 0.05, 95% CI -0.02 to 0.12; 9 trials, 719 infants; low-certainty evidence) and may slightly increase the risk of invasive infection (RR 1.14, 95% CI 0.99 to 1.31; RD 0.02, 95% CI -0.00 to 0.05; 11 trials, 3583 infants; low-certainty evidence).

AUTHORS' CONCLUSIONS

The available trial data indicate that advancing enteral feed volumes slowly (daily increments up to 24 mL/kg) compared with faster rates probably does not reduce the risk of NEC, death, or feed intolerance in very preterm or VLBW infants. Advancing the volume of enteral feeds at a slow rate may slightly increase the risk of invasive infection.

Early full enteral feeding for preterm or low birth weight infants

BACKGROUND

The introduction and advancement of enteral feeds for preterm or low birth weight infants is often delayed because of concerns that early full enteral feeding will not be well tolerated or may increase the risk of necrotising enterocolitis. Early full enteral feeding, however, might increase nutrient intake and growth rates; accelerate intestinal physiological, metabolic, and microbiomic postnatal transition; and reduce the risk of complications associated with intravascular devices for fluid administration.  OBJECTIVES: To determine how early full enteral feeding, compared with delayed or progressive introduction of enteral feeds, affects growth and adverse events such as necrotising enterocolitis, in preterm or low birth weight infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search Cochrane Central Register of Controlled Trials; MEDLINE Ovid, Embase Ovid, Maternity & Infant Care Database Ovid, the Cumulative Index to Nursing and Allied Health Literature, and clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials to October 2020.

SELECTION CRITERIA

Randomised controlled trials that compared early full enteral feeding with delayed or progressive introduction of enteral feeds in preterm or low birth weight infants.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal. Two review authors separately assessed trial eligibility, evaluated trial quality, extracted data, and synthesised effect estimates 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 evidence.

MAIN RESULTS

We included six trials. All were undertaken in the 2010s in neonatal care facilities in India. In total, 526 infants participated. Most were very preterm infants of birth weight between 1000 g and 1500 g. Trials were of good methodological quality, but a potential source of bias was that parents, clinicians, and investigators were not masked. The trials compared early full feeding (60 mL/kg to 80 mL/kg on day one after birth) with minimal enteral feeding (typically 20 mL/kg on day one) supplemented with intravenous fluids. Feed volumes were advanced daily as tolerated by 20 mL/kg to 30 mL/kg body weight to a target steady-state volume of 150 mL/kg to 180 mL/kg/day. All participating infants were fed preferentially with maternal expressed breast milk, with two trials supplementing insufficient volumes with donor breast milk and four supplementing with preterm formula.  Few data were available to assess growth parameters. One trial (64 participants) reported a slower rate of weight gain (median difference -3.0 g/kg/day), and another (180 participants) reported a faster rate of weight gain in the early full enteral feeding group (MD 1.2 g/kg/day). We did not meta-analyse these data (very low-certainty evidence). None of the trials reported rate of head circumference growth. One trial reported that the mean z-score for weight at hospital discharge was higher in the early full enteral feeding group (MD 0.24, 95% CI 0.06 to 0.42; low-certainty evidence). Meta-analyses showed no evidence of an effect on necrotising enterocolitis (RR 0.98, 95% CI 0.38 to 2.54; 6 trials, 522 participants; I² = 51%; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Trials provided insufficient data to determine with any certainty how early full enteral feeding, compared with delayed or progressive introduction of enteral feeds, affects growth in preterm or low birth weight infants. We are uncertain whether early full enteral feeding affects the risk of necrotising enterocolitis because of the risk of bias in the trials (due to lack of masking), inconsistency, and imprecision.