Low blood sugar in newborns
Low blood sugar level in newborn babies is also called neonatal hypoglycemia, refers to low blood sugar (glucose) in the first few days after birth. During an episode of hypoglycemia, there’s not enough glucose in the blood. The normal glucose range is approximately 70 to 150 mg/dl (milligrams of glucose per deciliter of blood). Neonatal hypoglycemia occurs when the newborn’s glucose level causes symptoms or is below the level considered safe for the baby’s age. Neonatal hypoglycemia is defined as a plasma glucose level of less than 30 mg/dL (1.65 mmol/L) in the first 24 hours of life and less than 45 mg/dL (2.5 mmol/L) thereafter, is the most common metabolic problem in newborns 1. Low blood sugar level in newborn occurs in about 1 to 3 out of every 1,000 births. In the majority of cases, hypoglycemia is temporary, easily treated and usually does not have serious consequences. There are several rare disorders in which hypoglycemia is recurrent and potentially life-threatening. However, with timely diagnosis and appropriate treatment, these can be effectively managed.
Low blood sugar in babies causes
Babies need blood sugar (glucose) for energy. Most of that glucose is used by the brain.
The baby gets glucose from the mother through the placenta before birth. After birth, the baby gets glucose from the mother through her milk or from formula, and the baby also produces it in the liver.
Glucose level can drop if:
- There is too much insulin in the blood. Insulin is a hormone that pulls glucose from the blood.
- The baby is not producing enough glucose.
- The baby’s body is using more glucose than is being produced.
- The baby is not able to feed enough to keep the glucose level up.
Low blood sugar level is more likely in infants with one or more of these risk factors:
- Born early, has a serious infection, or needed oxygen right after delivery
- Mother has diabetes (these infants are often larger than normal)
- Have slower than usual growth in the womb during pregnancy
- Are smaller or larger in size than normal for their gestational age.
Low blood sugar in babies prevention
If you have diabetes during pregnancy, work with your healthcare provider to control your blood sugar level. Be sure that your newborn’s blood sugar level is monitored after birth. A study by Joshi et al 2 suggested that in women with pregestational type 1 or type 2 diabetes, neonatal hypoglycemia can be avoided by aiming at an intrapartum blood glucose level of 72 – 126 mg/dl (4-7 mmol/L).
Signs and symptoms of hypoglycemia in newborn
Newborns with low blood sugar in the first or second day may not have symptoms or may have life-threatening central nervous system (CNS) and cardiopulmonary disturbances.
Symptoms of low blood sugar in babies can include the following:
- Hypotonia (poor muscle tone)
- Lethargy, apathy
- Poor feeding
- Jitteriness, seizures
- Congestive heart failure
- Cyanosis (bluish or greyish color of the skin, nails, lips or around the eyes)
- Apnea (temporary cessation of breathing)
- Hypothermia
Signs of low blood sugar in babies are associated with activation of the autonomic nervous system include the following:
- Anxiety, tremulousness
- Diaphoresis (sweating)
- Tachycardia (fast heart rate)
- Pallor (unhealthy pale appearance)
- Hunger, nausea, and vomiting
Clinical manifestations of hypoglycorrhachia [low glucose level in the cerebrospinal fluid (CSF)] or neuroglycopenia [shortage of glucose (glycopenia) in the brain] include the following:
- Headache
- Mental confusion, staring, behavioral changes, difficulty concentrating
- Visual disturbances (eg, decreased acuity, diplopia)
- Dysarthria
- Seizures
- Ataxia, somnolence, coma
- Stroke (hemiplegia, aphasia), paresthesias, dizziness, amnesia, decerebrate or decorticate posturing
If your baby has one of the risk factors for low blood sugar, nurses in the hospital will check your baby’s blood sugar level, even if there are no symptoms.
Also, blood sugar level is very often checked for babies with these symptoms:
- 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 in the first or second day of life may be asymptomatic .
Low blood sugar in newborns possible complications
Severe or persistent low blood sugar level may affect the baby’s mental function. In rare cases, heart failure or seizures may occur. However, these problems may also be due to the underlying cause of the low blood sugar, rather than a result of the low blood sugar itself.
Low blood sugar in newborns diagnosis
Newborns at risk for hypoglycemia should have a blood test to measure blood sugar level every few hours after birth. This will be done using a heel stick. The health care provider should continue taking blood tests until the baby’s glucose level stays normal for about 12 to 24 hours.
Other possible tests:
- Newborn screening for metabolic disorders, including blood and urine tests. Electrospray ionization-tandem mass spectrometry in asymptomatic persons allows earlier identification of clearly defined inborn errors of metabolism, including aminoacidemias, urea cycle disorders, organic acidurias, and fatty acid oxidation disorders.
- Serum insulin. When blood glucose is less than 40 mg/dL, plasma insulin concentration should be less than 5 and no higher than 10 µU/mL.
- Imaging studies. The detection of adenomas by celiac angiography has had limited success. The chance of detecting a tumor blush must be balanced against the potential risk of causing vascular trauma in infants younger than age 2 years.
Low blood sugar in newborns treatment
Newborns with a low blood sugar level will need to receive extra feedings with mother’s milk or formula. Babies who are breast-fed may need to receive extra formula if the mother is not able to produce enough milk. Hand expression and massage can help mothers express more milk. Sometimes a sugar gel may be given by mouth temporarily if there is not enough milk.
The newborn may need a sugar solution given through a vein (intravenously) if unable to eat by mouth, or if the blood sugar level is very low.
Treatment will be continued until the baby can maintain blood sugar level. This may take hours or days. Babies who were born early, have an infection, or were born at a low weight may need to be treated for a longer period of time.
If the low blood sugar continues, in rare cases, the baby may also receive medicine to increase blood sugar level. In very rare cases, newborns with very severe hypoglycemia who do not improve with treatment may need surgery to remove part of the pancreas (to reduce insulin production).
Emergency department care
Supportive therapy includes oxygen, establishing an intravenous (IV) line, and monitoring. Seizures unresponsive to correction of hypoglycemia should be managed with appropriate anticonvulsants. Marked acidosis (pH < 7.1) suggests shock or serious underlying disease and should be treated appropriately. The treatment goal is to maintain a blood glucose level of at least 45 mg/dL (2.5 mmol/L).
For the infant or child who does not drink but has intact airway protective reflexes, orogastric or nasogastric administration of oral liquids containing sugar may be performed.
Any child with documented hypoglycemia not secondary to insulin therapy should be hospitalized for careful monitoring and diagnostic testing.
Surgery
Surgical exploration usually is undertaken in severely affected newborns who are unresponsive to glucose and somatostatin therapy. Near-total resection of 85-90% of the pancreas is recommended for presumed congenital hyperinsulinism, which is most commonly associated with an abnormality of beta-cell regulation throughout the pancreas. Risks include the development of diabetes.
Low blood sugar in newborns prognosis
The outlook is good for newborns who do not have symptoms or who respond well to treatment. However, low blood sugar level can return in a small number of babies after treatment.
Hypoglycemia is more likely to return when babies are taken off feedings given through a vein before they are fully ready to eat by mouth.
Babies with more severe symptoms are more likely to develop learning problems. This is more often true for babies who are at a lower-than-average weight or whose mother has diabetes.
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