Neonatal Hypoglycemia: Symptoms, Causes, And Diagnosis

Identify the cause to start prompt treatment and prevent neurological damage in newborns.

Medically reviewed by Dr. Tashawna Stokes, MD Dr. Tashawna Stokes Dr. Tashawna StokesMD facebook_icontwitter_iconyoutube_icon Specialty: PediatricsExperience: 10 years
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Neonatal hypoglycemia is when a newborn’s plasma glucose levels dip below 30mg/dL (1.65mmol/L) within the first 24 hours of life and less than 45mg/dL (2.5mmol/L) after that. It is a common metabolic problem in newborns where blood sugar levels drop too low, raising the risk of severe complications.

Several reasons could cause a newborn’s sugar levels to drop. For instance, some healthy newborns may develop transient hypoglycemia while acclimatizing to extrauterine life after birth, which is usually normal.

Scroll down to know more about the causes, risk factors, signs and symptoms, diagnosis, and management of neonatal hypoglycemia.

Causes Of Neonatal Hypoglycemia

The depletion of stored glycogen combined with impaired gluconeogenesis (formation of glucose) results in hypoglycemia in babies.

Neonatal hypoglycemia can be due to various reasons (1).

  • Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a disorder of glucose homeostasis (regulation of blood sugar) and is a common cause of hypoglycemia in newborns.
  • Reduced glycogenolysis (making glucose from stored glycogen)
  • Failure of gluconeogenesis (formation of glucose)
  • Limited storage of glycogen due to premature birth or intrauterine growth problems
  • Depleted glycogen stores in babies with asphyxia (inadequate oxygen supply to the body), perinatal stress, or starvation
  • Adrenal insufficiency may cause hypoglycemia due to increased insulin sensitivity caused by depleted cortisol
  • Congenital hyperinsulinism can be due to abnormalities in the pancreatic cells
  • Early infections and disorders, such as sepsis or liver disease

Risk Factors For Neonatal Hypoglycemia

The following factors may increase the risk of neonatal hypoglycemia (2).

  • Macrosomia (larger baby than average size) usually occurs due to maternal diabetes mellitus during pregnancy
  • Low birth weight (less than 2kg)
  • Chorioamnionitis (infection of amniotic membranes) treatment during intrauterine life
  • Cesarean section
  • Low gestational age (prematurity)

Monitoring and appropriate feeding in higher risk newborns could help reduce the risk of complications.

Signs And Symptoms Of Neonatal Hypoglycemia

Some babies can be asymptomatic during the first couple of days of life. However, most infants develop life-threatening cardiopulmonary and central nervous system problems due to low blood glucose levels.

Common signs and symptoms of neonatal hypoglycemia could include (3):

Hypoglycemia usually activates the autonomic nervous system in non-diabetic individuals. You may notice the following symptoms if your baby has autonomic nervous system stimulation (3).

  • Increased heart rate
  • Pallor
  • Nausea
  • Vomiting
  • Hunger
  • Sweating
  • Anxiety
  • Quivering or shaking
  • Floppy or lose muscles

The drop in blood glucose can also lower the glucose levels in the cerebrospinal fluid (CSF). It can lead to a shortage of glucose in the brain, leading to the following manifestations.

  • Behavioral changes
  • Abnormal stare
  • Seizures
  • Coma
  • Stroke

Seek immediate medical care if you notice any symptoms of hypoglycemia in your newborn baby.

Diagnosis Of Neonatal Hypoglycemia

The following laboratory tests are ordered to diagnose neonatal hypoglycemia (4).

  • Plasma or serum glucose level test
  • Serum insulin test
  • Urinalysis to find the presence of organic acid and ketones
  • Metabolic errors screening to identify any inborn errors of metabolism

Additional tests could be required to determine or rule out the presence of adenoma (tumors) that could lead to hypoglycemia.

Most states offer baseline newborn metabolic screening. There are more comprehensive tests that are not routine, but considered if there is a strong family history of genetic causes for hypoglycemia.

Treatment For Neonatal Hypoglycemia

Immediate management helps to prevent neurological damages due to hypoglycemia in babies. The treatment options may include the following (5).

  • Early feeding with breast milk or formula can be beneficial for conscious and alert babies, and there is no risk of aspiration.
  • Intravenous (IV) nutrition could be preferred for babies who have the risk of aspiration and cannot feed themselves.
  • Diazoxide administration is useful to suppress insulin secretion in severe hyperinsulinemia due to adenoma or inborn metabolism errors.
  • Medications, such as dextrose, octreotide, and glucagon, are used to increase glucose levels.
  • Near-total pancreatic resection (surgical removal of 85-90% of the pancreas) is required if there is pancreatic adenoma-induced hypoglycemia, which is unresponsive to other treatments.

The American Academy of Pediatrics recommends admission to neonatal intensive care units and intravenous administration of dextrose (glucose) for the following cases of hypoglycemia (6).

  • Asymptomatic neonates with glucose lower than 25 mg/dL within the first four hours of life and less than 35 mg/dL at four to 24 hours of life
  • Symptomatic neonates with glucose less than 40 mg/dL
  • Persistent hypoglycemia regardless of frequent feeding

All high-risk infants are screened at birth and treated if required.

Complications Of Neonatal Hypoglycemia

Hypoglycemia could affect the brain and its functions. Neurological damage may result in long-term effects, such as seizures, poor cognitive function, personality disorders, and developmental delay (6).

The visual cortex that processes vision could also be affected. It may impact eyes and optic nerve development. Other complications include adverse effects on cardiovascular function. Severe prolonged hypoglycemia can be fatal if left untreated. Babies with asymptomatic hypoglycemia are often prone to long-term complications due to possible delays in diagnosis and interventions.

Frequently Asked Questions

1. What are some nursing interventions for neonatal hypoglycemia?

Enteral feedings, particularly more frequent breastfeeding, intravenous (IV) glucose infusion, and medication are some of the nursing interventions that can help to normalize blood glucose levels (4).

2. How long can hypoglycemia last in newborns?

Low blood glucose levels usually only last a few hours, although they can last 24 to 72 hours (7). Once your baby’s blood sugar levels return to normal, they would not have hypoglycemia issues. Low blood sugar can be severe and last for a long time in rare circumstances.

3. What is the first action taken by a nurse caring for a newborn with suspected hypoglycemia?

A fast-acting glucose source is given to the baby as part of the treatment. An early feeding could be as basic as a glucose and water mixture or a formula. Alternatively, a baby may require glucose via an intravenous line (8).

Neonatal hypoglycemia is not uncommon and may cause severe complications if left unaddressed. Since several factors can cause neonatal hypoglycemia, it is important to figure out the cause to determine the course of treatment. If your baby is premature, has low birth weight, or is larger than the average size, they may be at an increased risk of developing neonatal hypoglycemia. High-risk babies should thus be screened at birth. If your baby is born with neonatal hypoglycemia, speak with your doctor regarding its short-term and long-term management.

Key Pointers

  • Neonatal hypoglycemia is caused by the failure of gluconeogenesis or limited glycogen storage.
  • Low birth weight, maternal hypertension, and birth by c-section can increase the risk of hypoglycemia in neonates.
  • The common symptoms include increased heart rate, seizures, and congestive heart failure.
  • Early feeding and medications can help deal with this condition.


1. Hypoglycemia in a Newborn Baby; Lucile Packard Children’s Hospital Stanford
2. Hypoglycemia in a Newborn Baby; The University of Rochester Medical Center
3. Low Blood Sugar – Newborns; MedlinePlus; The US National Library of Medicine
4. Management Strategies for Neonatal Hypoglycemia;; The US National Library of Medicine
5. Neonatal Hypoglycemia; The American Academy of Pediatrics
6. Neonatal Hypoglycemia; The US National Library of Medicine
7. Checking blood glucose in newborn babies; Canadian Pediatric Society
8. Hypoglycemia in the Newborn; Cincinnati Children’s Hospital
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Dr. TaShawna Stokes is a mom to two beautiful daughters and currently practices in the Atlanta area. She received her undergraduate and medical degrees from Auburn University and The University of South Alabama. She completed her Pediatric Residency at Children’s Hospital of Los Angeles.

Read full bio of Dr. Tashawna Stokes
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