A Common Neonatal Emergency: Neonatal Hypoglycaemia

Abstract

Neonatal hypoglycaemia is a common neonatal emergency that usually occurs in the first few days of life. As babies with low blood sugar level could get irreversible brain injury, it is essential to identify newborn infants having risks to get hypoglycaemia so that timely and effective management could be provided to avoid unnecessary separation of mother and baby as well as the detrimental effects on development of newborns.

Introduction

Hypoglycaemia is one of the commonest metabolic disorders in neonates. Without early identification and effective treatment, it could lead to have permanent damage on neurodevelopment of newborns.

The diagnosis of neonatal hypoglycaemia is quite hard based only on physical examination as the symptoms being nonspecific and subtle. Therefore, it is essential to monitor the blood glucose level in those having high risk for developing hypoglycaemia in order to provide timely and effective management. Treatment of neonatal hypoglycaemia associated with abnormal clinical signs is an emergency.

Babies at risk of neonatal hypoglycaemia¹

Blood glucose level should be monitored in babies who are at risk of neonatal hypoglycaemia and in those having the following clinical signs and symptoms:

• Intrauterine growth retardation (Birth weight <2^nd centile, Table 1), or clinically wasted)
• Small-for-gestational age (SGA)/ Large for gestational age (LGA) ²
• Infants of diabetic mothers (regardless of type or treatment used during pregnancy)
• Infants of mothers taking beta-blockers (e.g., labetalol) in third trimester and / or at time of delivery
• Asphyxiated newborns ²
• Hypothermic neonates (<36.5’C) not attributed to environmental factors
• Newborns having
  • Suspected or confirmed early onset sepsis
  • Cyanosis or apnoea
  • Altered level of consciousness, seizures, hypotonia, excessive lethargy or high-pitched cry
  • Tremors/Jitteriness
  • Pallor/Coma
  • Reluctance to feed, only with abnormal clinical signs or if reluctance follows a period of normal feeding

In addition to the above factors, delayed initiation of breastfeeding more than an hour in healthy full-term infant is also an additional risk factor of neonatal hypoglycaemia.³

Table 1. Second Centile Birth Weight for boys and girls by week of gestation¹

Blood Sugar Level Measurement

Even though, blood glucose level could easily be measured with glucometer at bedside, in view of variation in value especially at low blood glucose level, laboratory plasma glucose level measurement is accepted as the most accurate method with the values expected to be about 10% higher than those with glucostrip.²

Optimal time to check Blood Sugar

The optimal timing for checking blood glucose level after birth has not been clearly determined yet. The American Association of Pediatrics (AAP)⁴ and Pediatric Endocrine Society (PES)⁵ suggest to check blood glucose 30 minutes after the first feed (usually in the first 2 hours of life) in late preterm and term neonates at risk.

Diagnosis of hypoglycaemia in neonates

The British Association of Perinatal Medicine (BAPM) defines hypoglycaemia as

• one blood glucose level < 1mmol/L at any time
• a single value <2.5 mmol/L in a newborn with abnormal clinical signs or
• a value < 2.0 mmol/L at the next measurement in a baby with a risk for impaired metabolic adaptation but without abnormal clinical signs.²

This framework targets to maintain the blood glucose level ≥2.6 mmol/L for 3 consecutive readings.⁶

Management of neonatal hypoglycaemia

The goal of management for neonatal hypoglycaemia is to prevent and treat acute symptomatic hypoglycaemia that can end up with permanent brain damage and long-term adverse outcomes.⁷

In order to meet the above goal, the management of neonatal hypoglycemia should be focused on 4 main purposes:

1. Prevention of hypoglycaemia in at-risk neonates
2. Prevention of unnecessary interventions that would improve spontaneously
3. Improvement of blood glucose levels in symptomatic neonates
4. Early identification of newborns with underlying severe hypoglycemic disease

Prevention of hypoglycaemia in at-risk neonates

In order to manage proactively to newborns at high risk of hypoglycaemia, proper support to establish correct position and attachment for breastfeeding and thermal care should be provided. It is vital to offer the initial breastfeed within the first hour of life and the feeding interval should not be more than 3 hours.

World Health Organization (WHO) and United Nations International Children’s Emergency Fund (UNICEF) suggested to initiate skin to skin contact immediately after birth for at least 60 minutes or immediately after first breastfeed to reduce the risk of hypoglycaemia.^8,9

For at-risk babies who do not show signs of effective breast feeding:

► Encourage continuous skin-to-skin contact with mother.

► Support mothers to establish correct position and attachment of breastfeeding

In very low-birth weight (VLBW) infants, intravenous (IV) glucose infusion has to be started soon after birth and blood glucose concentrations have to be checked promptly and frequently in view of the high risk of hypo- and hyperglycaemia.1

Then for the babies at risk of hypoglycaemia, blood glucose levels should be tested half an hour after feeding (post feed) as per AAP.7 If blood glucose level >2.6 mmol/L, the baby has to be fed every 2-3 hours intervals and the blood sugar is tested before feeding until blood glucose level > 2.6 mmol/L for three consecutive readings. Then the glucose monitoring should be stopped.

Blood glucose level thresholds for intervention2

Intervention is required for blood glucose:

• <1.0 mmol/L at any time
• <2.0 mmol/L in a baby at risk for hypoglycaemia
• <2.5 mmol/L with abnormal clinical signs
• <3.0 mmol/L in infants with suspected hyperinsulinism in the first 48 hours

Treatment of symptomatic hypoglycaemia

In the presence of hypoglycemic symptoms, or the blood sugar levels unable to keep above 2.6 mmol/L with oral feedings, IV fluid support with 10% dextrose should be commenced. ⁶

Per the most recent AAP guidelines in 2011, any symptomatic newborn with a blood glucose measuring less than 40 mg/dL (2.22 mmol/L) should receive IV dextrose.

If the at-risk newborn is asymptomatic and less than 4 hours old while blood glucose is less than 25 mg/dL (1.39 mmol/L) after a first feeding within 1 hour of birth, IV dextrose has to be administered.

If the glucose measures more than 25 mg/dL (1.39 mmol/L) but less than 40 mg/dL (2.22 mmol/L), the infant can be fed again and blood glucose, to be assessed 30 minutes after the feeding.

If the at-risk but asymptomatic newborn is 4 to 24 hours old and the blood glucose result is less than 35 mg/dL (1.94 mmol/L), feedings should be administered every 2 to 3 hours, although IV glucose may be administered at this point as well.

If the blood glucose measures 35 to 45 mg/dL (1.94-2.50 mmol/L), feedings may continue or IV glucose may be administered as needed. ⁶

Role of Dextrose IV fluid in symptomatic hypoglycaemia:

At the presence of hypoglycaemic symptoms or with the blood glucose level <1.0 mmol/L at any time, intravenous 10% dextrose bolus, 2 to 5 ml/kg has to go in, followed by intravenous infusion of 10% dextrose per daily fluid requirement (Glucose Infusion Rate/GIR: 6-8 mg/kg/minute).1

The blood glucose level has to be kept above 2.5mmol/L and if the desired effect cannot be achieved, the infusion rate of glucose has to be increased at 2 mg/kg/minute rate 4 with great precaution not to use glucose concentration more than 12.5% dextrose solution through peripheral lines. Central lines either Umbilical Venous Catheter/UVC nor Peripherally Inserted Central Catheter/PICC must be used if requiring dextrose concentration is more than 12.5% in view of the high risk of vessel injury.

Enteral feeds including breastfeeding should be continued if possible.

Infants admitted to Neonatal Intensive Care Unit (NICU) or Special Care Baby Unit (SCBU) for management of hypoglycaemia should remain under neonatal/ paediatric care in the postnatal ward for at least 72 hours.

Blood glucose monitoring and discharging home

Continue enteral feeds as tolerated and support breastfeeding (do not make nil orally unless enteral feeding is contraindicated). Increase feeds gradually, reducing IV glucose infusion accordingly when the blood glucose levels are stable (at least two consecutive readings ≥ 2.6mmol/L). Infants on three hourly breastfeeds may be discharged to postnatal ward as soon as blood glucose ≥ 2.6 mmol/L on three consecutive occasions.

Persistent or recurrent hypoglycemia

Persistent or recurrent hypoglycaemia (>2 measurements 1.0-1.9mmol/l during the first 48 hours after birth) can be the first presentation of an underlying disorder of glucose metabolism1 and consultation with paediatric endocrinologist ought to be done.

Conclusion

Many newborns are at risk of impaired metabolic adaptation leading to have hypoglycaemia. However, with prompt recognition of such risk factors and adequate energy intake, it is uncommon for newborn babies suffered from hypoglycaemia resulting irreversible brain damage. Therefore, it should be emphasised on the early prevention of hypoglycaemia by identification of at-risk neonates, initiation of early breastfeeding within first hour of life along with skin-to-skin contact and provision of breastfeeding support.

References

1. Levene I, Wilkinson D. Identification and management of neonatal hypoglycaemia in the fullterm infant (British Association of Perinatal Medicine-Framework for Practice). Arch Dis Child Educ Pract Ed. 2019;104(1):29–32.
2. Bulbul A, Uslu S. Neonatal hypoglycemia. SiSli Etfal Hastan Tip Bul / Med Bull Sisli Hosp [Internet]. 2016 Mar 29 [cited 2022 May 18];1–13. Available from: https: // www. journalagent.com/sislietfaltip/pdfs/SETB_50_1_1_13.pdf
3. Samayam P, Ranganathan PK, Kotari UD, Balasundaram R. Study of Asymptomatic Hypoglycemia in Full Term Exclusively Breastfed Neonates in First 48 Hours of Life. J Clin Diagn Res [Internet]. 2015;9(9):SC07-10.
4. Adamkin DH. Neonatal hypoglycemia. Semin Fetal Neonatal Med. 2017;22 (1) : 36–41.
5. Thorton PS, Stanley CA, De Leon DD, Recommendations from the Pediatric Endocrine Society for evaluation and management of persistent hypoglycemia in neonates, infants and children. J Pediatr. 2015:167:238-245
6. British Association of Periantal Medicine, Idenficatin and management of neonatal hypoglycaemia in the full term infant – A Framework for Practice. Br Assoc Perinat Med [Internet]. 2017;(December). Available from: http:// www. bapm. org/ publications/Hypoglycaemia F4P May 2017.pdf
7. Alsaleem M, Saadeh L, Kamat D. Neonatal Hypoglycemia: A Review. Clin Pediatr (Phila). 2019;58(13):1381–6.
8. World Health Organization. Skin-to-skin contact helps newborn breastfeed. (2020, August 7) Available from: https://www.who.int/westernpacific/news-room/feature-stories/item/ skin-to-skin-contact-helps-newborns-breastfeed/
9. UNICEF UNCF. From the First Making the case for From the First [Internet]. 2016. 1–104 p. Available from: https://data.unicef.org/resources/first-hour-life-new-report-breastfeeding-practices/

Author Information

Myat Thida Seinn
Consultant Paediatrician, Neonatal Intensive Care Unit, Yangon Children Hospital
MBBS, MMedSc (Paed), MRCPCH, DipUKMP, FRCPCH