Hypoglycemia in the newborn

What is hypoglycemia in the newborn?

Hypoglycemia is a condition that results from decrease in the blood glucose (sugar) level. It is often self-limited and commonly seen during the first 2-3 hours in healthy infants after birth.

Who is affected by hypoglycemia in the newborn?

Approximately two out of 1,000 newborn babies have hypoglycemia. Babies who are more likely to develop hypoglycemia include:

• Babies born to diabetic mothers are at a risk for developing hypoglycemia after delivery because the source of glucose (the mother's blood) is gone and the baby's high insulin level tends to metabolize the existing glucose faster.
• Small for gestational age, prematurity, low brith weight or growth-restricted babies may have limited glycogen stores in the liver or have immature liver function that results in hypoglycemia.

What causes hypoglycemia in the newborn?

Hypoglycemia may be caused by conditions that:

• Lower the amount of glucose in the bloodstream
• Result in lower storage of glycogen (sugar stored in liver)
• Cause increase use of glycogen stores (sugar stored in the liver)
• Prevent the use of glucose by the body

Glucose-a vital fuel:

Glucose is an important source of immediate energy for the body that is found in food. Glucose can also be stored as glycogen both in the liver and muscles for later use and if in excess it gets converted to fat.

Glucose is the main source of fuel for the brain, and is especially important for babies and young children. Complex hormonal and neurologic mechanisms regulate the amount of glucose between meals.

During pregnancy, the fetus gets glucose through the placenta from the mother. Some of the glucose gets stored as glycogen in the placenta and later in the fetal liver, heart, and muscles. These stores are important and provide glucose to baby’s brain during delivery and for nutrition after birth.

Many different conditions may be associated with hypoglycemia in the newborn, including the following:

• Inadequate maternal nutrition in pregnancy
• Excess insulin produced in a baby of a diabetic mother
• Severe hemolytic disease of the newborn (incompatibility of blood types of mother and baby)
• Birth defects and congenital metabolic diseases
• Birth asphyxia
• Low body temperature
• Liver disease
• Infection
• Deficiency of hormones from the Pituitary Gland

Why is hypoglycemia in the newborn a concern?

Sugar is one of the main sources of fuel for brain. If the blood sugar levels go lower it impairs the brain's ability to function. Severe or prolonged hypoglycemia may result in seizures and serious brain injury.

What are the symptoms of hypoglycemia in the newborn?

Symptoms of hypoglycemia may not be obvious in newborn babies and each baby may experience symptoms differently. The following are the most common symptoms of hypoglycemia:

• Cyanosis (blue coloring)
• Jitteriness
• Apnea (stopping breathing)
• Hypothermia (low body temperature)
• Poor body tone
• Poor feeding
• Lethargy
• Seizures

Since the symptoms of hypoglycemia may resemble other conditions or medical problems, it is advisable to consult your baby's physician for a diagnosis.

How is hypoglycemia in the newborn diagnosed?

A simple blood test for blood glucose levels can diagnose hypoglycemia. Blood may be drawn from a heel stick, with a needle from the baby's arm, or through an umbilical catheter (a tube placed in the baby's umbilical cord). Generally, a baby with low blood glucose levels will need treatment.

Treatment for hypoglycemia in the newborn:

The immediate treatment for hypoglycemia is giving the baby a rapid-acting source of glucose such as mixture of glucose/water or formula as an early feeding if baby is able to take by mouth. If baby is not responding and has seizures IV fluids containing glucose is the best choice to raise the blood glucose quickly. This will be followed by monitoring the blood glucose closely to see if hypoglycemia recurs again.

Specific treatment for hypoglycemia will be determined by your baby's physician based on:

• Detailed medical history, complete physical exam and initial lab testing. Baby may need more extensive testing to figure out the exact cause of the hypoglycemia. Sometimes an elective fast may be discussed with you as an option in the hospital settings to reach the correct diagnosis.

Prevention of hypoglycemia in the newborn:

There may not be any way to prevent hypoglycemia, only to watch carefully for the symptoms and treat as soon as possible. Mothers with diabetes whose blood glucose levels are in tight control will have lower amounts of glucose that go to the fetus. This will lower the fetal insulin production and reduce the risk of neonatal hypoglycemia.