What to Know About Hypoglycemia in a Newborn

Medically Reviewed by Dan Brennan, MD on July 30, 2022
4 min read

Being a new parent can be scary, and it can be even scarier when you have a newborn with hypoglycemia. However, newborn hypoglycemia, also called neonatal hypoglycemia, is very common. The American Academy of Pediatrics estimates that up to 25% of newborns are at risk of having hypoglycemia within their first 48 hours of life.

Glucose is the main sugar found in blood, and your body uses glucose as its main energy source. When your blood sugar dips too low, you may experience the following symptoms:

  • Fatigue
  • Headache
  • Nausea
  • Dizziness
  • Shaking
  • Irritability
  • Difficulty concentrating

Neonatal hypoglycemia is the diagnosis given to newborns with low blood sugar. All babies experience a drop in blood sugar immediately after birth, but some newborns experience an excessive drop. A hypoglycemia diagnosis will depend on your baby’s blood glucose levels, symptoms, and age.

When your baby is still in the womb, they receive glucose through the placenta. When they’re born, they no longer have access to the nutrients in the placenta. Because of this, their bodies may struggle to regulate their blood sugar at first.

So, why is it that some infants struggle with this more than others? Several conditions you may experience during your pregnancy can increase your child's risk of neonatal hypoglycemia. These include:

  • Inadequate nutrition
  • Uncontrolled diabetes, including gestational diabetes
  • Incompatible blood types between you and the baby
  • Liver disease
  • Infection

Factors affecting the baby that can increase their risk include:

  • Premature birth
  • Higher- or lower-than-average birth weight
  • Diabetes or another type of metabolic disease
  • Hormonal deficiency
  • Insufficient oxygen at birth

If you have high blood sugar when you're pregnant, your baby is at greater risk of having low blood sugar after birth. This is because, as the baby gets nutrients through the placenta, their body manufactures enough insulin to process their high blood sugar. Once they leave the womb, they're no longer receiving the same amount of sugar as they were from the placenta, but they maintain their high insulin levels. This causes their blood sugar to crash.

Babies born prematurely are also at a higher risk for hypoglycemia as they may not have enough glycogen stored in their body yet.

As mentioned above, the symptoms of hypoglycemia in adults may include nausea, fatigue, irritation, and headache. Infants, however, aren’t able to express to the people around them that they’re feeling these symptoms. Instead, you should keep an eye out for signs they might be hypoglycemic, which can include:

  • Shakiness or jitters
  • Pale or blue tint to the skin and/or lips
  • Low body temperature
  • Lethargy
  • Refusing to feed
  • Poor muscle tone
  • Trouble breathing
  • Seizures

If your doctor suspects your newborn has hypoglycemia, they’ll run a blood test to check your baby’s blood glucose levels.

Mild levels of hypoglycemia may stabilize on their own as your newborn drinks and digests their milk or formula. When this isn't the case, your doctor will explore treatment options such as:

  • Oral glucose
  • IV dextrose, a simple sugar that will raise your baby’s blood sugar
  • Tube feeding
  • Intramuscular injection of glucagon, a hormone that helps regulate blood sugar

The treatment your doctor chooses will depend on the severity of your baby's hypoglycemia, your baby’s gestational age and health history, and the reason for your baby’s hypoglycemia.

If your newborn is at high risk for hypoglycemia, your doctor may treat them preemptively with intravenous or oral glucose. Or, they may put the baby on a schedule of frequent formula feedings to ensure they get enough carbohydrates.

In most cases, babies with hypoglycemia will have no long-term issues once their sugars stabilize. However, there may be a correlation between babies with particularly severe hypoglycemia, or those who had delayed treatment for hypoglycemia, and long-term motor and mental impairments.

Occasionally, a newborn’s hypoglycemia may last longer than expected. This is almost always the result of a congenital disease or condition (one that was present when they were born). Such conditions include:

  • Hyperinsulinism, a disease where the body secretes too much insulin.
  • Beckwith–Wiedemann Syndrome, a condition in which certain parts of the body or body's systems grow larger than normal.
  • Sotos Syndrome, a genetic mutation causing fast growth and distinct physical features, among other characteristics.
  • Costello Syndrome, a rare condition caused by genetic mutations. This syndrome causes a range of symptoms that generally appear before 4 weeks of age.
  • Endocrine diseases. The endocrine system controls your hormones. Endocrine conditions that can cause hypoglycemia include hypopituitarism, adrenal hyperplasia, and hypothyroidism.
  • Metabolic disorders. Metabolic disorders happen when something disrupts the way your body metabolizes food. The metabolic disorders that can cause hypoglycemia include diabetes, maple syrup urine disease, and glycogen storage disorders, among others.

A newborn with hypoglycemia is sometimes, but not always, preventable. 

In situations with adequate prenatal care, your doctor will likely identify if your baby is high risk and work with you to lower your baby’s risk. To do this, they may make sure you get proper nutrition during pregnancy. They may also monitor your blood sugar levels if you have diabetes. In high-risk cases, your provider will likely have solutions ready during delivery to help get your newborn's blood sugar to a steady state.

In some cases, there's no way to prevent neonatal hypoglycemia. You can’t always predict if your baby will arrive early or if they'll be over- or undersized. You may not know ahead of time whether labor will be difficult or if your baby will have a congenital disease or disorder.

Because low blood sugar is common in newborns, your medical staff will watch for the signs of hypoglycemia and help you fix it if it appears. In most cases, your newborn will recover quickly and you’ll get to bring them home on schedule.