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Hypoglycaemia : preterm infants

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Guidance on the screening and management of hypoglycaemia in the first 48 hours of life for late preterm infants (born at 34+0-36+6 weeks gestation).

This document and complementary flow charts describe the criteria for screening and the subsequent management of hypoglycaemia in late preterm infants. For the purpose of this guidance this includes all infants born at 34+0 -36+6 gestation.

Such infants are at risk of hypoglycaemia during the first 48 hours due to impaired metabolic adaptation, and be potentially at risk of neurological damage when their blood glucose levels fall. They therefore require prompt and appropriate intervention.

This guidance does not apply to infants born 37 week and above; such infants should be managed separately according the Hypoglycaemia in Infants ≥ 37 weeks guideline 


All infants born at 34+0-36+6 week gestation should undergo routine screening for hypoglycaemia as detailed in this document.

Use of glucose buccal gel is not appropriate in late preterm infants and is therefore not part of this guideline.

All the advice regarding feeding and fluids within this document assume that there are no other medical issues.  Where this is not the case individualised care plans will be required.

The importance of parents as partners in care is reinforced throughout this guidance which includes a parent information leaflet which explains why their baby is receiving extra monitoring for blood glucose levels and how to raise concerns about their baby’s feeding pattern or well being.

Signs and Symptoms of Hypoglycaemia

All staff involved the screening and management for hypoglycaemia should be familiar with the signs and symptoms of hypoglycaemia.

Signs and Symptoms of Hypoglycaemia in the Neonate

Hypoglycaemia may present in a number of ways within the first 48 hours of life. These include;

  • Hypotonia
  • Lethargy (excessive sleepiness with or without abnormal tone)
  • Poor feeding
  • Hypothermia
  • Apnoea
  • Irritability
  • Pallor
  • Tachypnoea
  • Tachycardia or bradycardia
  • Seizures
  • Abnormal feeding behaviour (not waking for feeds, not sucking effectively, appearing unsettled and demanding very frequent feeds especially after a period of feeding well)

This list is not exhaustive. Medical review should be obtained for any generally unwell infant as these symptoms may warrant further investigation and consideration of other causes including sepsis

Measuring Blood Glucose

A late preterm infant who is at risk of hypoglycaemia should be screened with regular monitoring of the capillary glucose concentrations. 

Near patient testing devices tend to be less accurate in the lower range, especially < 2.0mmol/l [1] and therefore all low values (≤2.6mmol/L) require confirmation using blood gas analysis as this is considered the gold standard for measuring blood glucose.

Hand held glucometers should meet ISO standards (ISO15197:2013). If a handheld glucometer is used, low levels must be confirmed using an accurate method as cot-side monitors may be inaccurate in the lower ranges and require checking using a True Blood Glucose (TBG) to guide therapy. A TBG can be obtained by sending a formal laboratory sample but significant delays can occur in obtaining a result, alternatively a TBG can also be obtained from a blood gas analyser, where available, as these are equally reliable [2]. All units must ensure they have readily accessible methods for accurate measurement of a TBG . Each unit must be aware of the characteristics of any near patient testing device used in their hospital. 

Local Arrangements for Confirming Blood Glucose <2.6mmol/L

GG&C - GG&C Maternity and Neonatal units use the Precision Exceed Pro meter©. For this device glucose values 2.6 - 3.0mmol/l may prove to be <2.6mmol/l when a TBG is obtained from a blood gas machine or laboratory testing. Therefore a TBG should be obtained for:

  • Symptomatic babies with values below 3.0mmol/l (see section on symptoms of hypoglycaemia)
  • Asymptomatic babies with 2 values < 2.6mmol/l OR any value<2.0mmol/l
Monitoring the Asymptomatic Late Preterm Baby
  1. Identify all late preterm babies at birth and commence a hypoglycaemia/NEWS monitoring chart in labour ward. All babies should be risk assessed for criteria for hypoglycaemia monitoring and/or NEWS monitoring prior to leaving a labour ward environment

  2. Aim to prevent hypoglycaemia
    • Keep the baby warm - dry the baby well at birth, cover the baby whilst receiving skin to skin contact, put a hat on and avoid bathing until the temperature is stable and a warm environment is assured. This is likely to be after 24 hours of age. When dressing the baby, ensure that clothing is warmed first. Utilise skin-to-skin to warm the baby whenever needed.
    • Skin to skin and the first feed – it is vital that this baby has the opportunity to have uninterrupted skin contact immediately after the birth (including instrumental and caesarean birth). The baby should have the full “magical hour” episode.
      Do not assist the baby to feed too early before it is ready to attach correctly and feed effectively.  Ideally the first feed should commence within the first 60 minutes. Assist the mother to recognise feeding cues (rapid eye movements under the eye lids, mouth and tongue movements, body movements and sounds, sucking on a fist).
      If the baby has not feed by 90 minutes after the birth or is reluctant to feed, follow reluctant feeder guidance,  then start hand expressing and give the colostrum to the baby.
      For women who wish to formula feed give 10-15ml/kg 3 hourly.
    • Blood glucose monitoring and clinical surveillance – The first blood glucose should be taken prior to the second feed usually at around 2-4 hours old [3] [4]. Check the baby’s temperature, tone and respiratory rate at least 3 hourly to coincide with blood glucose measurements. Ensure that the baby is alert and normally responsive for their age and gestation. If the baby is unwell or has clinical signs of hypoglycaemia check the blood glucose immediately and alert the Paediatrician urgently.
    • Encourage effective feeding – Following the second feed, continue to offer lots of feeding opportunities, at least 3hly until blood glucose measurements have been > 2.5mmol on three consecutive occasions. Reinforce feeding cues; teach hand expressing and biological nurturing techniques to the mother early on as these will be essential for the late preterm baby who needs to feed often. Continue feeding support until mother and midwife are satisfied that effective feeding is established.
  3. Screen capillary blood samples for hypoglycaemia immediately prior to each feed (3 hourly) using a cot-side testing device. Aim to maintain a pre-feed blood glucose of ≥2.5 mmol/l.  If blood glucose values <2.5 mmol/l are obtained follow the management pathways.

  4. Discontinue monitoring when blood glucose concentrations have been > 2.5mmol/l on three consecutive occasions at least 3 hours apart. Observe feeding in hospital for at least a further 24 hours ensuring it is effective while remaining vigilant for the signs of hypoglycaemia. If signs of hypoglycaemia develop or there are concerns about feeding discuss with medical staff and consider taking a further blood glucose.

  5. After discontinuing regular glucose monitoring, continue feeding input
    • If the baby is alert and keen to waken and feed, then promote responsive feeding.
    • If the baby is still a bit sleepy, continue to waken and proactively offer feeds.
  6. Do not transfer babies with risk factors for impaired metabolic adaptation and hypoglycaemia to community care  for at least 24 hours until you are satisfied that the baby is maintaining blood glucose levels and feeding well.
Managing the late Preterm Baby - Based on Blood Glucose Results With or Without Clinical Signs of Hypoglycaemia

Normal Pathway – Blood Glucose >2.5mmol/l

  • If 3 consecutive values, at 3hly intervals, fall in this zone, monitoring may cease.

Green Zone – Blood Glucose 2.0 – 2.5 mmol/l - Increased vigilance and feeding support

  • Offer an additional feed if willing and continue frequent feeds at least 3hly thereafter.
  • Observe a breastfeed and ensure good attachment and effective feeding. Encourage skin contact and biological nurturing. Proactively encourage hand expressing.
  • If two consecutive measurements fall within the Green Zone - - Treat as Amber Pathway

Amber Zone – Blood Glucose 1.0 - 1.9 mmol/l - Supplement and Paediatric review

  • Inform Paediatrician
  • Feed volumes must be increased.  Initially by an extra 10ml/kg/feed above current intake. 
    For breast fed babies this will require top-ups. Top ups should be EBM* if sufficient available, otherwise formula should be used. Donor Breast Milk is an option and ensure families are aware this is available and can be used in this scenario.
  • Measure Glucose 1hr post feed.  If >2.5mmol/l, continue supplements and resume prefeed testing
  • If subsequent prefeed glucose values have improved to lie in the green zone but still remain <2.6 mmol/l, increase top up volumes by one further increment of 5-10 ml/kg/feed
  • If baby will not take, or does not tolerate, supplements then admit to SCBU/TC  for NG feeds
  • Two consecutive measurements in the Amber Zone -- Treat as Red Pathway

Red Zone – Blood Glucose <1.0 mmol/l - Admit to SCBU

  • Notify Paediatrician immediately for all babies who are symptomatic or whose blood Glucose is <1.0mmol/l
  • Admit to SCBU and check TBG on the blood gas machine. Take one of the following actions immediately:

1- Babies who are asymptomatic and have not had an adequate feed prior to admission

  • Administer an immediate feed of at least 10 ml/kg (EBM by preference or formula).
    If the baby will not feed orally, administer the feed by NG tube.  Re-check blood glucose after 1hr.
  • If > 2.6 mmol/l resume frequent, 3 hly, feeding of at least 10ml/kg/feed and monitor Glc before each feed
  • If 2.0-2.6 mmol/l start hourly feeds of 5ml/kg/feed (120ml/kg/day) check glucose before each feed (hourly).
  • If < 2.0 mmol/l after initial feed or if still hypoglycaemic on 1hly feeds, treat with IV Glucose as   below 

2 - Babies who cannot tolerate enteral feeds or whose blood glucose remains <2.6mmol/l despite frequent NG feeds (as above)  OR who become symptomatic

  • Site IV and, if symptomatic or Glc <1.0mmol/l, give 2.5ml/kg 10% Dextrose slow IV bolus
  • Start 90ml/kg/day of 10% dextrose or TPN
  • Enteral feeds may continue initially but if hypoglycaemia persists despite increasing volumes of IV Glucose then a temporary cessation of enteral feeds may be required.
  • Monitor Blood Glucose hourly and titrate the glucose infusion rate to achieve normoglycaemia
  • If the baby has an ongoing requirement of ≥120 ml/kg/day of milk / 10% glucose to maintain normoglycaemia, refer to the guideline for refractory hypoglycaemia  

*It is usual to use the mother’s own breast milk for top-ups.  However mother’s own EBM may be unavailable or insufficient for the required volume of top-up.  Under these circumstances donor EBM or infant formula should be used.

Appendix 2: Hypoglycaemia Monitoring Chart - Late Preterm Infants 34-36+6 Weeks Gestation

1. Beardsall K. Measurement of glucose levels in the newborn. Early HumDev. 2010;86(5):263-267 

2. Dahlberg M, Whitelaw A. Evaluation of HemoCue Blood Glucose Analyzer for the instant diagnosis of hypoglycaemia in newborns. (1997) Scand J Clin Lab Invest Dec; 57(8):719-24 1

3. Aynsley-Green A, Soltesz G. (1986) Disorder of blood glucose homeostasis in the neonate. In: Roberton NRC, ed.Textbook of neonatology. Edinburgh: Churchill Livingstone,.

4. Hetenyi G, Cowan JS. Glucoregulation in the newborn.  (1980) Can J Physiol Pharmacol ;58:879-88.

Editorial Information

Last reviewed: 01 July 2020

Next review: 01 July 2023

Author(s): Dr Natalie Smee – Paediatric Trainee RHC; Dr Lesley Jackson – Neonatal Consultant RHC

Version: 1

Co-Author(s): Other Professionals consulted: Ms Gillian Bowker - Infant Feeding Advisor GG&C; Mrs Anisa Patel - Neonatal Pharmacist RHC; Mrs Lauren Williams - Neonatal Pharmacist RHC