An Overview of Neonatal Hypoglycemia

Symptoms, Causes, Diagnosis, and More

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Neonatal hypoglycemia, or low blood sugar in a newborn, occurs when a newborn’s blood glucose levels are less than 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.  

Prevalence

Neonatal hypoglycemia affects one to five newborns per 1,000 births according to one report from the American Academy of Pediatrics. 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 had severe hypoglycemia, and another 19 had more than one episode of hypoglycemia. 

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

The researchers concluded the 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.

A 2017 study reported in The Journal of Maternal-Fetal & Neonatal Medicine found 16 percent of newborns with no other risk factors born at any early gestational age (before 37 weeks) had neonatal hypoglycemia. The researchers also concluded that incidences of neonatal hypoglycemia with classic risk factors were much like those in the general population. In other words, risk factors do not have to play a part in the development of low blood sugar in newborns.

Causes and Risk Factors

Babies get glucose from their mother 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

Symptoms

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
  • Hyperthermia (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 doctors 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 doctor.

Diagnosis

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 doctor 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

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 doctor as soon as possible.

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Article Sources
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