Neonatal hypoglycemia occurs when a newborn has low blood sugar levels in the first few days after birth. It occurs in about 1-3 out of every 1,000 births. A normal blood sugar level, also known as glucose, is crucial for a baby’s energy and brain development. Severe or prolonged hypoglycemia may result in seizures and serious brain injury.

During pregnancy, the baby gets all nutrients, including glucose from the mother, through the umbilical cord in a constant stream. At birth, the umbilical cord is clamped then cut effectively removing the baby’s source of nutrients. Most babies have glucose stored in the liver, which helps maintain a normal blood sugar until the baby begins to nurse. Colostrum, the very early milk produced by a mother is very high in glucose. Some babies have difficulty producing enough glucose to maintain their blood sugar levels prior to nursing.

Glucose levels can drop if there is too much insulin in the blood, if the body is not producing enough glucose, if it is using more than can be produced, and if the baby is not feeding enough to keep the glucose levels up. 

For example, low glucose levels are more common for infants who:

  • Were born prematurely or are under significant stress such as having difficulty breathing or when they are battling an infection. The premature liver does not have adequate glucose stores to support a normal blood sugar for long if at all. The stressed newborn metabolizes glucose faster than a healthy full term baby.
  • Have a mother with diabetes due to over production of insulin.
  • Have low thyroid hormone levels (hypothyroidism)
  • Had poor growth in the womb again because the liver did not adequately store glucose prior to delivery.

Infants with low blood sugar don’t always show symptoms. But nurses and doctors know to check blood sugars in high-risk babies. If there are symptoms, they may include:

  • Bluish-colored or pale skin
  • Breathing problems, such as pauses in breathing (apnea), rapid breathing, or a grunting sound
  • Irritability or listlessness
  • Loose or floppy muscles
  • Poor feeding or vomiting
  • Problems keeping the body warm
  • Tremors, shakiness, sweating, or seizures

Infants with low blood sugar levels will need to receive extra feedings with breast milk or formula. The baby may also need a sugar solution given intravenously if he or she is unable to eat by mouth, or if the blood sugar is very low. For the great majority of babies, hypoglycemia resolves quickly once the baby begins to nurse.


  • Neonatal hypoglycemia is when a newborn baby has low blood sugar levels (glucose) in the first few days after birth.
  • Low glucose levels are common in premature babies or those born under significant stress
  • Symptoms include tremors, shaking or changes in skin color.
  • Treatment includes extra feedings of breast milk and formula, or a sugar solution being administered intravenously.

Last reviewed by Sara Connolly, MD. Review Date: December 2018


  1. National Institutes of Health. Low Blood Sugar: Newborns.
  2. Boston Children’s Hospital. Hypoglycemia and Low Blood Sugar.


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