An Overview of Neonatal Hypoglycemia

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Neonatal hypoglycemia, or low blood sugar in a newborn, occurs when a newborn’s blood glucose levels are less than the baby’s body needs. Glucose is the main fuel source for the body and brain. In a newborn, low blood sugar has many causes.

It can also cause problems, including breathing and feeding issues. The condition is treatable, but if not detected, it could be fatal, especially if an underlying condition is to blame.  

Neonatal Hypoglycemia symptoms
Verywell / JR Bee 


Neonatal hypoglycemia affects up to about 4 per 1,000 full-term births according to some studies. It is usually associated with risk factors, including the mother’s age at the time of birth, if the mother is diabetic, or if the baby is too small or too large. In fact, the incidence in high-risk newborns can be as high as 30 percent.

Research reported in The Journal of Pediatrics finds more than half of newborns with risk factors could become hypoglycemic. Risk factors, according to the 2012 study, include being born too small or too large, having a diabetic mother, or being born late-preterm (birth at 34 through 36 week's gestation). Researchers in this study looked at 514 infants who were born at 35 weeks or later and identified as being at risk for hypoglycemia. Blood glucose testing was done within the first 48 hours after birth.  

A little more than half of the newborns were hypoglycemic, 19 percent had severe hypoglycemia, and another 19 percent had more than one episode of hypoglycemia. 

The newborns who had three risk factors had the highest risk for severe hypoglycemia.

The researchers concluded that neonatal hypoglycemia is common for newborns with specific risk factors and multiple risk factors put the newborns at a higher risk. The researchers did not make any conclusions about long-term outcomes.

Causes and Risk Factors

Babies get glucose from their mothers through the placenta before they are born. After birth, their sources of glucose are breast milk and formula.  Glucose is also produced in the liver. Blood sugar may drop when there is too much insulin (a hormone that pulls glucose from the blood), if the baby is not producing enough or using too much or if the baby is unable to feed.

Some newborns have certain risk factors that make it easier for them to develop neonatal hypoglycemia. These may include:

  • Being born too early
  • Infection
  • Need for oxygen after delivery
  • Mother with diabetes
  • Having a slow growth while in the womb
  • Being smaller or larger in size than normal


In newborns, a blood glucose level of 30 mg/dL (milligrams per deciliter) in the first 24 hours of life and less than 45 mg/dL constitutes neonatal hypoglycemia. Symptoms of neonatal hypoglycemia are not always obvious in a newborn. Moreover, each newborn may experience symptoms differently. 

Symptoms may include:

  • Bluish or pale skin color
  • Apnea (breathing pauses) or rapid breathing
  • Hypothermia (low body temperature)
  • Jitteriness, grunting, and/or irritability
  • Poor feeding or vomiting
  • Lethargy (general feeling of unwellness)
  • Tremors or seizures

If your newborn is experiencing any of these symptoms, talk to the nurses and healthcare providers about blood tests. Even if the newborn does not have symptoms and you know there are risk factors, it's still best to discuss these with your healthcare provider.


Diagnosis of neonatal hypoglycemia is done with a serum glucose test. It is a blood test that measures blood sugar in a newborn using a heel stick, an easy and minimally invasive way do blood work for newborns where blood is drawn from the heel of the foot.

If blood sugar is low, the healthcare provider will keep checking until it is at normal levels for 12 to 24 hours. Sometimes, additional newborn testing is done to look for metabolic disorders, conditions that affect the normal metabolic process and may cause low blood sugar.


Treatment of neonatal hypoglycemia depends on the presence of hypoglycemia symptoms, breast milk supply, and the ability to nurse or feed with a bottle and formula. Newborns with low blood sugar will need extra breast milk or formula feedings. Some newborns may need a sugar solution (glucose) intravenously, or through a vein, especially if the baby is unable to feed by mouth or if blood glucose is very low.

Treatment will continue for a few hours or days, or until the newborn can maintain normal blood sugar levels. Premature babies, babies with infections, or those born at a low birth weight may need to be treated for longer periods. If low blood sugar continues, the newborn will be given medication to increase blood sugar. In very rare cases, newborns with very low blood sugar who do not improve may need part of the pancreas removed to reduce insulin production. 

A Word From Verywell

The outlook is good for babies born with low blood sugar that do not have symptoms and even with symptoms when they respond well to treatment. It is unlikely hypoglycemia will affect babies as they grow, as long as they receive treatment quickly.

Very low levels of blood sugar that remain persistent may affect a newborn’s mental function. They may also affect the heart and cause seizures. However, this is rare and newborns who are affected by low blood sugar long-term usually have an underlying medical condition for which they will need further treatment. If you think your newborn may have another health condition contributing to low blood sugar, talk to a pediatrician or your healthcare provider as soon as possible.

Frequently Asked Questions

  • What are the signs of hypoglycemia in newborns?

    Signs of hypoglycemia (low blood sugar) in newborns include pale or bluish skin color, apnea (temporary pauses in breathing), rapid breathing, hypothermia (low body temperature), jitteriness, grunting, irritability, poor feeding or vomiting, lethargy, and tremors or seizures.

  • What causes low blood sugar in newborns?

    The causes of low blood sugar in newborns can include too much insulin present in the blood, not producing enough glucose, using more glucose than what is produced, or being unable to receive enough glucose from feeding.

  • What is the normal level of blood glucose in a newborn?

    The normal level of blood glucose in a newborn is slightly below 2 mmol/L (millimoles per liter). Two or three days after birth, this number rises to the adult level of 3 mmol/L or above.

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Gardner SL, Carter BS, Enzman-Hines MI, Niermeyer S. Merenstein & Gardner's Handbook of Neonatal Intensive Care. 9th ed. St. Louis, MO: Elsevier; 2020. 435-436.

  2. Sharma A, Davis A, Shekhawat PS. Hypoglycemia in the preterm neonate: etiopathogenesis, diagnosis, management and long-term outcomes. Transl Pediatr. 2017;6(4):335-348. doi:10.21037/tp.2017.10.06

  3. Harris DL, Weston PJ, Harding JE. Incidence of neonatal hypoglycemia in babies identified as at risk. J Pediatr. 2012;161(5):787-91. doi:10.1016/j.jpeds.2012.05.022

  4. Stanford Children's Health. Hypoglycemia in a newborn baby.

  5. Sweet CB, Grayson S, Polak M. Management strategies for neonatal hypoglycemia. J Pediatr Pharmacol Ther. 2013;18(3):199-208. doi:10.5863/1551-6776-18.3.199

  6. MedlinePlus. Low blood sugar - newborns.

  7. MedlinePlus. Low blood sugar - newborns.

  8. Checking blood glucose in newborn babiesPaediatr Child Health. 2004;9(10):718-748. PMID:19688082