The effect of early feeding on the neonatal blood glucose level at 1-hour of age

Oral dextrose gel to prevent hypoglycaemia in at-risk neonates

BACKGROUND

Neonatal hypoglycaemia is a common condition that can be associated with brain injury. Current practice usually includes early identification of at-risk infants (e.g. infants of diabetic mothers; preterm, small- or large-for-gestational-age infants), and prophylactic measures are advised. However, these measures often involve use of formula milk or admission to the neonatal unit. Dextrose gel is non-invasive, inexpensive and effective for treatment of neonatal hypoglycaemia. Prophylactic dextrose gel can reduce the incidence of neonatal hypoglycaemia, thus potentially reducing separation of mother and baby and supporting breastfeeding, as well as preventing brain injury. This is an update of a previous Cochrane Review published in 2021.

OBJECTIVES

To assess the effectiveness and safety of oral dextrose gel in preventing hypoglycaemia before first hospital discharge and reducing long-term neurodevelopmental impairment in newborn infants at risk of hypoglycaemia.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and Epistemonikos in April 2023. We also searched clinical trials databases and the reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing oral dextrose gel versus placebo, no intervention, or other therapies for the prevention of neonatal hypoglycaemia. We included newborn infants at risk of hypoglycaemia, including infants of mothers with diabetes (all types), high or low birthweight, and born preterm (< 37 weeks), age from birth to 24 hours, who had not yet been diagnosed with hypoglycaemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias. We contacted investigators to obtain additional information. We used fixed-effect meta-analyses. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included two studies conducted in high-income countries comparing oral dextrose gel versus placebo in 2548 infants at risk of neonatal hypoglycaemia. Both of these studies were included in the previous version of this review, but new follow-up data were available for both. We judged these two studies to be at low risk of bias in 13/14 domains, and that the evidence for most outcomes was of moderate certainty. Meta-analysis of the two studies showed that oral dextrose gel reduces the risk of hypoglycaemia (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.79 to 0.95; risk difference (RD) -0.06, 95% CI -0.10 to -0.02; 2548 infants; high-certainty evidence). Evidence from two studies showed that there may be little to no difference in the risk of major neurological disability at two years of age after oral dextrose gel (RR 1.00, 95% CI 0.59 to 1.68; 1554 children; low-certainty evidence). Meta-analysis of the two studies showed that oral dextrose gel probably reduces the risk of receipt of treatment for hypoglycaemia during initial hospital stay (RR 0.89, 95% CI 0.79 to 1.00; 2548 infants; moderate-certainty evidence) but probably makes little or no difference to the risk of receipt of intravenous treatment for hypoglycaemia (RR 1.01, 0.68 to 1.49; 2548 infants; moderate-certainty evidence). Oral dextrose gel may have little or no effect on the risk of separation from the mother for treatment of hypoglycaemia (RR 1.12, 95% CI 0.81 to 1.55; two studies, 2548 infants; low-certainty evidence). There is probably little or no difference in the risk of adverse effects in infants who receive oral dextrose gel compared to placebo gel (RR 1.22, 95% CI 0.64 to 2.33; two studies, 2510 infants; moderate-certainty evidence), but there are no studies comparing oral dextrose with other comparators such as no intervention or other therapies. No data were available on exclusive breastfeeding after discharge.

AUTHORS' CONCLUSIONS

Prophylactic oral dextrose gel reduces the risk of neonatal hypoglycaemia in at-risk infants and probably reduces the risk of treatment for hypoglycaemia without adverse effects. It may make little to no difference to the risk of major neurological disability at two years, but the confidence intervals include the possibility of substantial benefit or harm. Evidence at six to seven years is limited to a single small study. In view of its limited short-term benefits, prophylactic oral dextrose gel should not be incorporated into routine practice until additional information is available about the balance of risks and harms for later neurological disability. Additional large follow-up studies at two years of age or older are required. Future research should also be undertaken in other high-income countries, low- and middle-income countries, preterm infants, using other dextrose gel preparations, and using comparators other than placebo gel. There are three studies awaiting classification and one ongoing study which may alter the conclusions of the review when published.

Relationships between feeding and glucose concentrations in healthy term infants during the first five days after birth-the Glucose in Well Babies Study (GLOW)

Background

The World Health Organization recommends breastfeeding be commenced as soon as possible after birth. Amongst other benefits, early feeding is expected to support the metabolic transition after birth, but effects on blood glucose concentrations are controversial. We sought to describe the changes in interstitial glucose concentrations after feedings over the first five postnatal days.

Participants and Methods

In healthy singleton term infants, all feeds were recorded using a smart phone app. Glucose concentrations were measured by blinded interstitial monitoring, calibrated by heel-prick capillary samples 2-4 times/d. Feeding sessions were included if a start and end time were recorded, and if the interval between the start of successive feeds was >90 min. The area under the glucose concentration curve (AUC) was calculated by trapezoidal addition from baseline (median of the 3 measurements before the beginning of the session). The maximum deviation (MD) was the greatest change in glucose concentration (positive or negative) from baseline to the next feeding session or 180 min, whichever came first. Data were analyzed using Stata V17 and are presented as mean (95% CI) in mmol/L.

Results

Data were available for 62 infants and 1,770 feedings. The glucose response to breastfeeding was not different from zero on day 1 [day 1 AUC 0.05 (-0.00, 0.10), MD 0.06 (-0.05, 0.16)], but increased thereafter (day 3 (AUC 0.23 (0.18, 0.28), MD 0.41 (0.32, 0.50), day 5 AUC 0.11 (0.06, 0.16), MD 0.28 (0.18, 0.37), p < 0.001 for age effect). Glucose response increased with increased duration of breastfeeding (<30 min AUC 0.06 (0.02,0.09), MD 0.12 (0.04,0.19), >30 min AUC 0.20 (0.16, 0.23) MD 0.37 (0.30, 0.44), p < 0.001 for duration effect) and this was observed even in the first 2 days (<30 min AUC-0.02 (-0.06, 0.03), MD -0.06 (-0.15, 0.03), >30 min AUC 0.12 (0.08, 0.16), MD 0.19 (0.11, 0.27), overall p < 0.001 for age x duration interaction). In feeding sessions that were not breastfeeding, the glucose response was greater after formula than after expressed human milk [AUC 0.29 (0.15, 0.29), MD 0.48 (-0.12, 0.61)], and greater after feed volumes >20 ml than <10 ml [20-30 ml AUC 0.19 (0.01, 0.27), MD 0.23 (-0.01, 0.46)].

Conclusion

The glucose response to feeding in the days after birth increases with postnatal age and duration of the feeding episode. Breastfeeding for <30 min has little effect on glucose concentrations in the first two days.

Oral dextrose gel to prevent hypoglycaemia in at-risk neonates

BACKGROUND

Neonatal hypoglycaemia is a common condition that can be associated with brain injury. Current practice usually includes early identification of at-risk infants (e.g. infants of diabetic mothers; preterm, small- or large-for-gestational-age infants), and prophylactic measures are advised. However, these measures usually involve use of formula milk or admission to the neonatal unit. Dextrose gel is non-invasive, inexpensive and effective for treatment of neonatal hypoglycaemia. Prophylactic dextrose gel can reduce the incidence of neonatal hypoglycaemia, thus potentially reducing separation of mother and baby and supporting breastfeeding, as well as preventing brain injury.  This is an update of a previous Cochrane Review published in 2017.  OBJECTIVES: To assess the effectiveness and safety of oral dextrose gel given to newborn infants at risk of hypoglycaemia in preventing hypoglycaemia and reducing long-term neurodevelopmental impairment.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2020, Issue 10) in the Cochrane Library; and Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions(R) on 19 October 2020. 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 randomised controlled trials (RCTs) and quasi-RCTs comparing oral dextrose gel versus placebo, no intervention, or other therapies for the prevention of neonatal hypoglycaemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias. We contacted investigators to obtain additional information. We used fixed-effect meta-analyses. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included two studies conducted in high-income countries comparing oral dextrose gel versus placebo in 2548 infants at risk of neonatal hypoglycaemia. Of these, one study was included in the previous version of this review. We judged these two studies to be at low risk of bias, and that the evidence for most outcomes was of moderate certainty. Meta-analysis of the two studies showed that oral dextrose gel reduces the risk of hypoglycaemia (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.79 to 0.95; risk difference (RD) -0.06, 95% CI -0.10 to -0.02; 2548 infants; high certainty evidence). One study reported that oral dextrose gel probably reduces the risk of major neurological disability at two years' corrected age (RR 0.21, 95% CI 0.05 to 0.78; RD -0.05, 95% CI -0.09 to 0.00; 360 infants; moderate certainty evidence). Meta-analysis of the two studies showed that oral dextrose gel probably reduces the risk of receipt of treatment for hypoglycaemia during initial hospital stay (RR 0.89, 95% CI 0.79 to 1.00; 2548 infants; moderate certainty evidence) but makes little or no difference to the risk of receipt of intravenous treatment for hypoglycaemia (RR 1.01, 0.68 to 1.49; 2548 infants; moderate certainty evidence). Oral dextrose gel may have little or no effect on the risk of separation from the mother for treatment of hypoglycaemia (RR 1.12, 95% CI 0.81 to 1.55; two studies, 2548 infants; low certainty evidence). There is probably little or no difference in the risk of adverse events in infants who receive oral dextrose gel compared to placebo gel (RR 1.22, 95% CI 0.64 to 2.33; two studies, 2510 infants; moderate certainty evidence), but there are no studies comparing oral dextrose with other comparators such as no treatment, standard care or other therapies. No data were available on exclusive breastfeeding after discharge.

AUTHORS' CONCLUSIONS

Oral dextrose gel reduces the risk of neonatal hypoglycaemia in at-risk infants and probably reduces the risk of major neurological disability at two years of age or greater without increasing the risk of adverse events compared to placebo gel. Additional large follow-up studies at two years of age or older are required. Future research should also be undertaken in low- and middle-income countries, preterm infants, using other dextrose gel preparations, and using comparators other than placebo gel. There are three studies awaiting classification and one ongoing study which may alter the conclusions of the review when published.

ABM Clinical Protocol #1: Guidelines for Glucose Monitoring and Treatment of Hypoglycemia in Term and Late Preterm Neonates, Revised 2021

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical conditions 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.

Clinical Aspects of Neonatal Hypoglycemia: A Mini Review

Introduction: Neonatal hypoglycemia is common and a preventable cause of brain damage. The goal of management is to prevent or minimize brain injury. The purpose of this mini review is to summarize recent advances and current thinking around clinical aspects of transient neonatal hypoglycemia. Results: The groups of babies at highest risk of hypoglycemia are well defined. However, the optimal frequency and duration of screening for hypoglycemia, as well as the threshold at which treatment would prevent brain injury, remains uncertain. Continuous interstitial glucose monitoring in a research setting provides useful information about glycemic control, including the duration, frequency, and severity of hypoglycemia. However, it remains unknown whether continuous monitoring is associated with clinical benefits or harms. Oral dextrose gel is increasingly being recommended as a first-line treatment for neonatal hypoglycemia. There is some evidence that even transient and clinically undetected episodes of neonatal hypoglycemia are associated with adverse sequelae, suggesting that prophylaxis should also be considered. Mild transient hypoglycemia is not associated with neurodevelopmental impairment at preschool ages, but is associated with low visual motor and executive function, and with neurodevelopmental impairment and poor literacy and mathematics achievement in later childhood. Conclusion: Our current management of neonatal hypoglycemia lacks a reliable evidence base. Randomized trials are required to assess the effects of different prophylactic and treatment strategies, but need to be adequately powered to assess outcomes at least to school age.

Newborn Plasma Glucose Concentration Nadirs by Gestational-Age Group

BACKGROUND

The glucose concentrations and times to nadir for newborns of all gestational ages when intrapartum glucose-containing solutions are not routinely provided are unknown.

OBJECTIVE

To characterize and compare patterns of initial glucose concentration nadirs by gestational-age groups.

METHODS

A cross-sectional cohort study of 1,366 newborns born in 1998 at the University of Arkansas for Medical Sciences, appropriate for gestational age, nonasphyxiated, nonpolycythemic, and not infants of diabetic mothers, were included. Initial plasma glucose concentrations, before intravenous fluids or feedings, were plotted against time after birth for 4 gestational-age groups (full term [FT], ≥37-42 weeks; late preterm [LPT], ≥34 and < 37 weeks; preterm [PT], ≥28 and < 34 weeks; and extremely low gestational age newborns [ELGAN], 23 and < 28 weeks of gestation).

RESULTS

ELGAN had the earliest nadir at 61 ± 4 min, followed by PT newborns (71 ± 2 min), and then LPT and FT newborns at 92-93 min. The time to nadir for ELGAN and PT newborns was significantly earlier than for FT newborns. Glucose nadir concentrations for ELGAN, PT, and LPT newborns were significantly lower than for FT newborns. LPT newborns' pattern of glucose paralleled those of FT newborns, with values approximately 5-6 mg/dL lower during the first 3 h.

CONCLUSION

Plasma glucose nadirs occurred at different times among gestational-age groups during the early postnatal period as follows: ELGAN < PT < LPT ≈ FT. In order to potentially prevent low glucose concentrations at the time of the nadir, exogenous glucose should be provided to all newborns as soon as possible after birth.

Standards of admission capillary blood glucose levels in cesarean born neonates

BACKGROUND

Neonatal hypoglycemia (NH) and cutoffs remain undefined. Our center screens all cesarean-delivered (CD) neonates for NH. We sought to define standards of admission capillary blood glucose levels (ACBGLs) in CD neonates who were at the lowest risk for hypoglycemia.

METHODS

Of 4947 neonates, 519 met all 14 inclusion criteria. These highly-selected neonates were apparently the healthiest, least-stressed, earliest to be admitted to nursery and at lowest-risk for hypoglycemia. For each CD, cord blood gases and glucose were determined and each infant was screened for blood glucose at nursery admission.

RESULTS

Sampling age was 41.6±15.3 minutes, a mean ACBGL of 52.3±10.7 mg/dL, and percentiles as follows: 1st percentile, 29.2; 3rd, 33.6; 5th, 35.0; 10th, 39.0; 25th, 46.0; 50th, 51.0; 75th, 58.0; 90th, 67.0; 95th, 71.0; 97th, 73.0, and 99th, 84.4. ACBGL rose significantly with increasing gestational age (P=0.004), increasing cord blood glucose (P<0.001), decreasing cord blood pH (P<0.001) and decreasing sampling age (P=0.027).

CONCLUSIONS

Setting uniform ACBGL cutoffs for NH definition is unachievable due to the enormous heterogeneity among newborns. Hence, we provide group-based ACBGL standards in CD neonates. We propose setting ACBGL cutoffs for use in CD neonates: 1) hypoglycemia: ACBGL <5th percentile (<35 mg/dL); and 2) interventional hypoglycemia: ACBGL <1st percentile (<30 mg/dL).

The Effect of Early Feeding on Initial Glucose Concentrations in Term Newborns

OBJECTIVE

To evaluate the influence of early feeding on initial glucose concentrations in healthy term newborns who were not at risk for hypoglycemia.

STUDY DESIGN

This retrospective observational study was conducted at the University of Arkansas for Medical Sciences where universal early glucose screening was standard of care for newborn infants. Plasma glucose concentrations were compared in term infants born in 2008 who were not at risk for neonatal hypoglycemia and who were fed before (early feeders) and after (late feeders) their initial glucose screens. Multiple linear regression models were built to determine whether glucose concentrations differed significantly between early vs late feeders.

RESULTS

In the 315 early and 572 late feeders, the mean (SD) age of first feeding was 0.9 (0.6) and 3.8 (2.0) hours, respectively. The age at initial glucose specimen collection was 2.2 (1.1) and 1.8 (0.8) hours, respectively. The initial glucose concentration was not higher in early vs late feeders (51.8 ± 11.9 vs 55.5 ± 13.3 mg/dL; P < .001). In linear regression analyses of all infants, the mean initial glucose concentration was 3.61 (95% CI 1.75-5.48) mg/dL lower in early vs late feeders.

CONCLUSIONS

Early feeding in otherwise healthy term newborns did not increase initial glucose concentrations compared with newborns who fed later (ie, fasted). Before direct evidence is available, these observations may be instructive for managing early asymptomatic hypoglycemia in at-risk newborns.

What is a normal blood glucose?

Glucose is the key metabolic substrate for tissue energy production. In the perinatal period the mother supplies glucose to the fetus and for most of the gestational period the normal lower limit of fetal glucose concentration is around 3 mmol/L. Just after birth, for the first few hours of life in a normal term neonate appropriate for gestational age, blood glucose levels can range between 1.4 mmol/L and 6.2 mmol/L but by about 72 h of age fasting blood glucose levels reach normal infant, child and adult values (3.5-5.5 mmol/L). Normal blood glucose levels are maintained within this narrow range by factors which control glucose production and glucose utilisation. The key hormones which regulate glucose homoeostasis include insulin, glucagon, epinephrine, norepinephrine, cortisol and growth hormone. Pathological states that affect either glucose production or utilisation will lead to hypoglycaemia. Although hypoglycaemia is a common biochemical finding in children (especially in the newborn) it is not possible to define by a single (or a range of) blood glucose value/s. It can be defined as the concentration of glucose in the blood or plasma at which the individual demonstrates a unique response to the abnormal milieu caused by the inadequate delivery of glucose to a target organ (eg, the brain). Hypoglycaemia should therefore be considered as a continuum and the blood glucose level should be interpreted within the clinical scenario and with respect to the counter-regulatory hormonal responses and intermediate metabolites.

Nursing and midwifery management of hypoglycaemia in healthy term neonates

EXECUTIVE SUMMARY:

OBJECTIVES

The primary objective of this review was to determine the best available evidence for maintenance of euglycaemia* in healthy term neonates, and the management of asymptomatic hypoglycaemia in otherwise healthy term neonates.

INCLUSION CRITERIA

TYPES OF STUDIES: The review included any relevant published or unpublished studies undertaken between 1995 and 2004. Studies that focus on the diagnostic accuracy of point-of-care devices for blood glucose screening and/or monitoring in the neonate were initially included as a subgroup of this review. However, the technical nature and complexity of the statistical information published in diagnostic studies retrieved during the literature search stage, as well as the considerable volume of published research in this area, suggested that it would be more feasible to analyse diagnostic studies in a separate systematic review.

TYPES OF PARTICIPANTS

The review focused on studies that included healthy term (37- to 42-week gestation) appropriate size for gestational age neonates in the first 72 h after birth.

EXCLUSIONS

•  preterm or small for gestational age newborns; •  term neonates with a diagnosed medical or surgical condition, congenital or otherwise; •  babies of diabetic mothers; •  neonates with symptomatic hypoglycaemia; •  large for gestational age neonates (as significant proportion are of diabetic mothers). TYPES OF INTERVENTION: All interventions that fell within the scope of practice of a midwife/nurse were included: •  type (breast or breast milk substitutes), amount and/or timing of feeds, for example, initiation of feeding, and frequency; •  regulation of body temperature; •  monitoring (including screening) of neonates, including blood or plasma glucose levels and signs and symptoms of hypoglycaemia. Interventions that required initiation by a medical practitioner were excluded from the review.

TYPES OF OUTCOME MEASURES

Outcomes that were of interest included: •  occurrence of hypoglycaemia; •  re-establishment and maintenance of blood or plasma glucose levels at or above set threshold (as defined by the particular study); •  successful breast-feeding; •  developmental outcomes. TYPES OF RESEARCH DESIGNS: The review initially focused on randomised controlled trials reported from 1995 to 2004. Insufficient randomised controlled trials were identified and the review was expanded to include additional cohort and cross-sectional studies for possible inclusion in a narrative summary.

SEARCH STRATEGY

The major electronic databases, including MEDLINE/PubMed, CINAHL, EMBASE, LILACS, Cochrane Library, etc., were searched using accepted search techniques to identify relevant published and unpublished studies undertaken between 1995 and 2004. Efforts were made to locate any relevant unpublished materials, such as conference papers, research reports and dissertations. Printed journals were hand-searched and reference lists checked for potentially useful research. The year 1995 was selected as the starting point in order to identify any research that had not been included in the World Health Organisation review, which covered literature published up to 1996. The search was not limited to English language studies. ASSESSMENT OF QUALITY: Three primary reviewers conducted the review assisted by a review panel. The review panel was comprised of nine nurses with expertise in neonatal care drawn from senior staff in several metropolitan neonatal units and education programs. Authorship of journal articles was not concealed from the reviewers. Methodological quality of each study that met the inclusion criteria was assessed by two reviewers, using a quality assessment checklist developed for the review. Disagreements between reviewers were resolved through discussion or with the assistance of a third reviewer.

DATA EXTRACTION AND ANALYSIS

Two reviewers used a data extraction form to independently extract data relating to the study design, setting and participants; study focus and intervention(s); and measurements and outcomes. As only one relevant randomised controlled trial was found, a meta-analysis could not be conducted nor tables constructed to illustrate comparisons between studies. Instead, the findings were summarised by a narrative identifying any relevant findings that emerged from the data.

RESULTS

Seven studies met the inclusion criteria for the objective of this systematic review. The review provided information on the effectiveness of three categories of intervention - type of feeds, timing of feeds and thermoregulation on two of the outcome measures identified in the review protocol - prevention of hypoglycaemia, and re-establishment and maintenance of blood or plasma glucose levels above the set threshold (as determined by the particular study). There was no evidence available on which to base conclusions for effectiveness of monitoring or developmental outcomes, and insufficient evidence for breast-feeding success. Given that only a narrative review was possible, the findings of this review should be interpreted with caution. The findings suggest that the incidence of hypoglycaemia in healthy, breast-fed term infants of appropriate size for gestational age is uncommon and routine screening of these infants is not indicated. The method and timing of early feeding has little or no influence on the neonatal blood glucose measurement at 1 h in normal term babies. In healthy, breast-fed term infants the initiation and timing of feeds in the first 6 h of life has no significant influence on plasma glucose levels. The colostrum of primiparous mothers provides sufficient nutrition for the infant in the first 24 h after birth, and supplemental feeds or extra water is unnecessary. Skin-to-skin contact appears to provide an optimal environment for fetal to neonatal adaptation after birth and can help to maintain body temperature and adequate blood glucose levels in healthy term newborn infants, as well as providing an ideal opportunity to establish early bonding behaviours.

IMPLICATIONS FOR PRACTICE

The seven studies analysed in this review confirm the World Health Organisation's first three recommendations for prevention and management of asymptomatic hypoglycaemia, namely: 1 Early and exclusive breast-feeding is safe to meet the nutritional needs of healthy term newborns worldwide. 2 Healthy term newborns that are breast-fed on demand need not have their blood glucose routinely checked and need no supplementary foods or fluids. 3 Healthy term newborns do not develop 'symptomatic' hypoglycaemia as a result of simple underfeeding. If an infant develops signs suggesting hypoglycaemia, look for an underlying condition. Detection and treatment of the cause are as important as correction of the blood glucose level. If there are any concerns that the newborn infant might be hypoglycaemic it should be given another feed. Given the importance of thermoregulation, skin-to-skin contact should be promoted and 'kangaroo care' encouraged in the first 24 h after birth. While it is important to main the infant's body temperature care should be taken to ensure that the child does not become overheated.

Two hour blood glucose levels in at-risk babies: An audit of Canadian guidelines

BACKGROUND

The Canadian guidelines recommend blood glucose (BG) screening starting at 2 h of age in asymptomatic 'at-risk' babies (including small-for-gestational-age [SGA] and large-for-gestational-age [LGA] infants), with intervention cut-offs of 1.8 mmol/L and 2.6 mmol/L. The present study reviews and audits this practice in full-term newborn populations.

METHODS

A literature review meta-analyzed BG values in appropriate-for-gestational age (AGA) term newborns to establish normal 1 h, 2 h and 3 h values. A clinical review audited screening of 'at-risk' SGA and LGA term newborns, evaluating both clinical burden and validity.

RESULTS

The review included six studies, although none clearly defined the plasma glucose standard. The pooled mean (plasma) BG level in AGA babies 2 h of age was 3.35 mmol/L (SD=0.77), significantly higher than 1 h levels (3.01 mmol/L, SD=0.96). In the audit, 78 SGA and 142 LGA babies each had an average of 6.0 and 4.7 BG tests, respectively. The mean 2 h BG levels for SGA (3.42 mmol/L, SD=1.02) and LGA (3.31 mmol/L, SD=0.66) babies did not differ significantly from the AGA pooled mean. Receiver operating characteristic curves showed that 2 h BG levels in LGA and SGA babies predicted later hypoglycemia (defined as a BG level lower than 2.6 mmol/L), but sensitivities and specificities were poor.

CONCLUSIONS

Published 2 h BG levels for AGA babies are higher than 1 h values and are similar to audited 2 h levels in SGA and LGA babies. Clinically, 2 h levels are predictive of later hypoglycemia but may require repeat BG testing. Audit is an important tool to validate national guidelines, to minimize their burden and to maximize their utility.

Hyperglycemia and adverse pregnancy outcome study: neonatal glycemia

OBJECTIVE

The goal was to describe the temporal pattern of neonatal plasma glucose levels and associations with maternal glucose levels, cord serum C-peptide levels, and neonatal size and adiposity.

METHODS

A total of 17,094 mothers and infants were included in the Hyperglycemia and Adverse Pregnancy Outcome Study (15 centers in 9 countries). Mothers underwent a 75-g, 2-hour, oral glucose tolerance test (OGTT) at 24 to 32 weeks of gestation. Cord blood and neonatal blood samples were collected. Biochemical neonatal hypoglycemia was defined as glucose levels of <10th percentile (2.2 mmol/L). Clinically identified hypoglycemia was ascertained through medical record review and associations were assessed.

RESULTS

Plasma glucose concentrations were stable during the first 5 hours after birth. Maternal glucose levels were weakly positively associated with biochemical neonatal hypoglycemia (odds ratios: 1.07-1.14 for 1-SD higher OGTT glucose levels). Frequency of neonatal hypoglycemia was higher with higher cord C-peptide levels (odds ratio: 11.6 for highest versus lowest C-peptide category). Larger and/or fatter infants were more likely to have hypoglycemia (P < .001), and infants with hypoglycemia tended to have a higher frequency of cord C-peptide levels of >90th percentile.

CONCLUSIONS

Mean neonatal plasma glucose concentrations varied little in the first 5 hours after birth, which suggests normal postnatal adjustment. Biochemical and clinical hypoglycemia were weakly related to maternal OGTT glucose measurements but were strongly associated with elevated cord serum C-peptide levels. Larger and/or fatter infants were more likely to develop hypoglycemia and hyperinsulinemia. These relationships suggest physiologic relationships between maternal glycemia and fetal insulin production.

Neonatal glucose metabolism in offspring of mothers with varying degrees of hyperglycemia during pregnancy

The definition of neonatal hypoglycemia is controversial. Operational thresholds of blood glucose values at which intervention should be considered have been proposed. IDM and GDM infants frequently exhibit a pronounced drop of plasma glucose immediately after birth. This exaggerated physiological decline of glucose is transient and is seldom accompanied by suppressed lipolysis or clinical symptoms. It is generally attributed to hyperinsulinism elicited by maternal hyperglycemia. Alternative substrates for CNS i.e. lactate and astrocyte glycogen may explain lack of symptoms. Similarly low glucose values later on may cause clinical symptoms. Glucose production rates vary from attenuated to normal likely reflecting differences in maternal glycemic control. The HAPO study of around 25,000 non-diabetic pregnancies revealed strong associations between glucose values (75g OGTT) and increased fetal size and hyperinsulinemia at birth - findings adding strong support to the maternal hyperglycemia - fetal hypinsulinism theory. Mothers with the highest fasting glucose had infants with the highest frequency of clinical neonatal hypoglycaemia (4,6%).

Does breastfeeding influence risk of type 2 diabetes in later life? A quantitative analysis of published evidence

BACKGROUND

Observational evidence suggests that having been breastfed in infancy may reduce the prevalence of type 2 diabetes in later life.

OBJECTIVE

The objective was to examine the influence of initial breastfeeding on type 2 diabetes and blood glucose and insulin concentrations.

DESIGN

A systematic review of published studies identified 1010 reports; 23 examined the relation between infant feeding and type 2 diabetes in later life or risk factors for diabetes. Risk factors in infants were examined separately from those in children and adults. All estimates were pooled by using fixed-effect models; differences <0 and ratios <1 imply a beneficial effect of breastfeeding.

RESULTS

Subjects who were breastfed had a lower risk of type 2 diabetes in later life than did those who were formula fed (7 studies; 76 744 subjects; odds ratio: 0.61; 95% CI: 0.44, 0.85; P = 0.003). Children and adults without diabetes who had been breastfed had marginally lower fasting insulin concentrations than did those who were formula fed (6 studies; 4800 subjects; percentage difference: -3%; 95% CI: -8%, 1%; P = 0.13); no significant difference in fasting glucose concentrations was observed. Breastfed infants had lower mean preprandial blood glucose (12 studies; 560 subjects; mean difference: -0.17 mmol/L; 95% CI: -0.28, -0.05 mmol/L; P = 0.005) and insulin (7 studies; 291 subjects; mean difference: -2.86 pmol/L; 95% CI: -5.76, 0.04 pmol/L; P = 0.054) concentrations than did those who were formula fed.

CONCLUSION

Breastfeeding in infancy is associated with a reduced risk of type 2 diabetes, with marginally lower insulin concentrations in later life, and with lower blood glucose and serum insulin concentrations in infancy.

Nursing and midwifery management of hypoglycaemia in healthy term neonates

OBJECTIVES

The primary objective of this review was to determine the best available evidence for maintenance of euglycaemia in healthy term neonates, and the management of asymptomatic hypoglycaemia in otherwise healthy term neonates.

INCLUSION CRITERIA

The review included any relevant published or unpublished studies undertaken between 1995 and 2004. Studies that focus on the diagnostic accuracy of point-of-care devices for blood glucose screening and/or monitoring in the neonate were initially included as a subgroup of this review. However, the technical nature and complexity of the statistical information published in diagnostic studies retrieved during the literature search stage, as well as the considerable volume of published research in this area, suggested that it would be more feasible to analyse diagnostic studies in a separate systematic review.The review focused on studies that included healthy term (37- to 42-week gestation) appropriate size for gestational age neonates in the first 72 h after birth.All interventions that fell within the scope of practice of a midwife/nurse were included:Interventions that required initiation by a medical practitioner were excluded from the review.Outcomes that were of interest included:The review initially focused on randomised controlled trials reported from 1995 to 2004. Insufficient randomised controlled trials were identified and the review was expanded to include additional cohort and cross-sectional studies for possible inclusion in a narrative summary.

SEARCH STRATEGY

The major electronic databases, including MEDLINE/PubMed, CINAHL, EMBASE, LILACS, Cochrane Library, etc., were searched using accepted search techniques to identify relevant published and unpublished studies undertaken between 1995 and 2004. Efforts were made to locate any relevant unpublished materials, such as conference papers, research reports and dissertations. Printed journals were hand-searched and reference lists checked for potentially useful research. The year 1995 was selected as the starting point in order to identify any research that had not been included in the World Health Organisation review, which covered literature published up to 1996. The search was not limited to English language studies.

ASSESSMENT OF QUALITY

Three primary reviewers conducted the review assisted by a review panel. The review panel was comprised of nine nurses with expertise in neonatal care drawn from senior staff in several metropolitan neonatal units and education programs. Authorship of journal articles was not concealed from the reviewers. Methodological quality of each study that met the inclusion criteria was assessed by two reviewers, using a quality assessment checklist developed for the review. Disagreements between reviewers were resolved through discussion or with the assistance of a third reviewer.

DATA EXTRACTION AND ANALYSIS

Two reviewers used a data extraction form to independently extract data relating to the study design, setting and participants; study focus and intervention(s); and measurements and outcomes.As only one relevant randomised controlled trial was found, a meta-analysis could not be conducted nor tables constructed to illustrate comparisons between studies. Instead, the findings were summarised by a narrative identifying any relevant findings that emerged from the data.

RESULTS

Seven studies met the inclusion criteria for the objective of this systematic review. The review provided information on the effectiveness of three categories of intervention - type of feeds, timing of feeds and thermoregulation on two of the outcome measures identified in the review protocol - prevention of hypoglycaemia, and re-establishment and maintenance of blood or plasma glucose levels above the set threshold (as determined by the particular study). There was no evidence available on which to base conclusions for effectiveness of monitoring or developmental outcomes, and insufficient evidence for breast-feeding success.Given that only a narrative review was possible, the findings of this review should be interpreted with caution. The findings suggest that the incidence of hypoglycaemia in healthy, breast-fed term infants of appropriate size for gestational age is uncommon and routine screening of these infants is not indicated. The method and timing of early feeding has little or no influence on the neonatal blood glucose measurement at 1 h in normal term babies. In healthy, breast-fed term infants the initiation and timing of feeds in the first 6 h of life has no significant influence on plasma glucose levels. The colostrum of primiparous mothers provides sufficient nutrition for the infant in the first 24 h after birth, and supplemental feeds or extra water is unnecessary.Skin-to-skin contact appears to provide an optimal environment for fetal to neonatal adaptation after birth and can help to maintain body temperature and adequate blood glucose levels in healthy term newborn infants, as well as providing an ideal opportunity to establish early bonding behaviours.

IMPLICATIONS FOR PRACTICE

The seven studies analysed in this review confirm the World Health Organisation's first three recommendations for prevention and management of asymptomatic hypoglycaemia, namely:1 Early and exclusive breast-feeding is safe to meet the nutritional needs of healthy term newborns worldwide.2 Healthy term newborns that are breast-fed on demand need not have their blood glucose routinely checked and need no supplementary foods or fluids.3 Healthy term newborns do not develop 'symptomatic' hypoglycaemia as a result of simple underfeeding. If an infant develops signs suggesting hypoglycaemia, look for an underlying condition. Detection and treatment of the cause are as important as correction of the blood glucose level.If there are any concerns that the newborn infant might be hypoglycaemic it should be given another feed. Given the importance of thermoregulation, skin-to-skin contact should be promoted and 'kangaroo care' encouraged in the first 24 h after birth. While it is important to main the infant's body temperature care should be taken to ensure that the child does not become overheated.

The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study

OBJECTIVE

The objective of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study is to clarify unanswered questions on associations of maternal glycemia, less severe than overt diabetes mellitus, with risks of adverse pregnancy outcome. This report describes the background and design of the HAPO Study.

METHODS

HAPO is a 5-year investigator-initiated prospective observational study that will recruit approximately 25000 pregnant women in 10 countries. HAPO utilizes a Central Laboratory for measurement of key metabolic variables, a Clinical Coordinating Center, a Data Coordinating Center, and an independent Data Monitoring Committee. Glucose tolerance is assessed by a 75 g 2-h OGTT at 24-32 weeks' gestation. Results are unblinded to the woman and her caregivers if: fasting plasma glucose >5.8 mmol/l, 2-h plasma glucose >11.1 mmol/l or any plasma glucose <2.5 mmol/l. Random plasma glucose measurement is performed at 34-37 weeks or if symptoms suggest hyperglycemia; results are unblinded for values > or = 8.9 mmol/l. Sociodemographic and health history data are collected via questionnaire and medical record abstraction. Maternal blood is obtained for measurement of serum C-peptide and hemoglobin A1c (HbA(1C)), cord blood for serum C-peptide and plasma glucose, and a capillary specimen is taken between 1 and 2 h following delivery for neonatal plasma glucose. Neonatal anthropometrics are obtained, and follow-up data are collected at 4-6 weeks post-delivery. The primary outcomes to be assessed in relation to maternal glycemia are cesarean delivery, increased fetal size (macrosomia/LGA/obesity), neonatal morbidity (hypoglycemia), and fetal hyperinsulinism.