Low blood sugar or hypoglycemia is not unusual for babies immediately after birth, but it’s important to prevent it from lasting more than a few days. Supplemental feedings can often help blood sugars get back to a normal level.

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Neonatal hypoglycemia is low blood sugar levels in newborn infants. It’s more common in premature and high risk newborns, with one study reporting that 30–60% of high risk infants in the neonatal intensive care unit (NICU) are hypoglycemic.

Neonatal hypoglycemia typically occurs immediately after a baby is born as they transition to life outside the placenta.

While neonatal hypoglycemia generally only lasts somewhere between a few hours to a few days, it’s important that parents and doctors keep an eye out for symptoms to prevent prolonged or more serious hypoglycemia.

Neonatal hypoglycemia means that an infant has low blood glucose levels. Glucose is the term for sugar in your blood. The American Academy of Pediatrics set the cutoff for healthy blood glucose at 47 mg/dL in a newborn.

Before they’re born, babies receive glucose through the placenta. After they’re born, this glucose needs to come through breast milk or formula, although some is also produced by the liver. If an infant doesn’t get sufficient glucose from feedings, they may experience hypoglycemia.

Newborns may also experience hypoglycemia if there’s too much insulin in the blood, they don’t produce enough glucose, or they use more glucose than what their body produces.

There has been a lot of discussion about typical blood glucose levels right after a baby is born while they adjust to not getting glucose through the placenta.

It’s currently accepted that within the first 2 hours of life, glucose levels may drop down to 30 mg/dL before rising to 45 mg/dL and finally stabilizing at around 12 to 24 hours of life.

A newborn infant has neonatal hypoglycemia when their glucose falls below these expected levels.

Symptoms of neonatal hypoglycemia can include:

One thing to keep in mind is that other conditions can have similar symptoms to neonatal hypoglycemia, so it’s important to discuss your child’s symptoms with their doctor.

Reasons for neonatal hypoglycemia can include:

Neonatal hypoglycemia is more common in:

  • preterm infants (especially those with low birth weights)
  • infants with serious infections or who needed oxygen right after delivery
  • infants born to a parent with diabetes
  • newborns large for their gestational age
  • infants born to women who have taken certain medications like terbutaline
  • stressful birthing situations

Extremely low blood glucose levels in newborns can result in:

  • apnea (prolonged pauses in breathing)
  • seizures
  • brain damage

The exact treatment for neonatal hypoglycemia can vary depending on the baby’s gestational age, general health, and blood sugar levels.

In general, infants with low blood sugar will need a fast-acting glucose source. This may take the form of:

  • a water and glucose mixture like oral dextrose gel
  • breast milk
  • formula

This may be given as an extra feeding, or it may be given through an IV line.

Additional glucose will generally continue to be given until blood sugar levels normalize, which may be a few hours or days. If low blood sugar continues for a prolonged period of time, medications like corticosteroids or glucagon may be given.

Although more research into the long-term effects of neonatal hypoglycemia is still needed, the most recent research indicates that when hypoglycemia appears during the first 10 days and clears up quickly, it’s likely to have few serious complications.

It’s important to prevent severe long-term neonatal hypoglycemia, though, as it can lead to disabilities, cerebral palsy, and death.

Neonatal hypoglycemia is diagnosed through blood testing.

Newborns with symptoms of hypoglycemia should have their blood glucose levels tested. If risk factors for neonatal hypoglycemia are present, an infant may have their blood glucose levels tested right after birth and frequently over the next few hours, even if no symptoms of hypoglycemia are displayed.

Neonatal hypoglycemia is not always preventable, but keeping an eye out for risk factors and testing the glucose levels of at-risk infants can prevent prolonged hypoglycemia and more serious complications.

Feeding within the first hour after birth and offering early supplementation for infants with feeding difficulties can also help to prevent more serious complications from developing. Pregnant individuals with diabetes should also work with their doctors to ensure their blood sugars are well controlled during their pregnancy.

Will my baby need to go to the NICU if they have hypoglycemia after they are born?

Many factors determine how serious neonatal hypoglycemia is. Some newborns will need to spend time in the NICU, but infants with less serious cases may not require it.

Is high or low blood sugar more common in newborn infants?

Neonatal hypoglycemia (low blood sugar) is more common than neonatal hyperglycemia (high blood sugar).

What options do I have for supplementing my baby’s feeds if my breast milk volume is low?

If your baby has hypoglycemia following birth and requires additional food, you can try to express additional breast milk for them with pumping or hand expression. Donor milk and formula can also be used to supplement feeds.

In some cases, doctors may offer a mixture of glucose and water.

Hypoglycemia or low blood sugar can occur in newborns right after they are born. If your baby has risk factors for neonatal hypoglycemia, like a birthing parent with diabetes, you can expect medical professionals to test their blood to determine their blood sugar levels.

In many cases, neonatal hypoglycemia will naturally correct within a day or two as an infant begins to regularly feed. In some cases, supplemental feeding is required.

You should speak with your child’s doctor if you are concerned about severe or prolonged neonatal hypoglycemia.