Neonatal Hypoglycemia (Low Blood Sugar) and Birth Injury
Glucose is crucial to brain development, as it is one of the only sources of energy the brain can use. Neonatal hypoglycemia is a condition in which a baby’s blood sugar falls very low within a few days after birth. These low glucose levels impair the growth process, and brain cells start to die. Neonatal hypoglycemia is one of the most common neonatal metabolic issues, and one of the most easily treated.
Infants with neonatal hypoglycemia (NH) experience a dangerous drop in their level of glucose (also known as blood sugar) in the first few days after birth. Babies need glucose for energy, and most of the glucose is used by the brain. Before birth, the baby gets glucose from the mother through the placenta. After birth, the baby gets glucose from breast milk or formula. Glucose is also produced in the baby’s liver.
Neonatal hypoglycemia is one of the most common metabolic problems in babies, and severe NH is one of the leading causes of brain injury. Neonatal hypoglycemia is not difficult to recognize, and usually it is very easily treated. Untreated NH, however, can have serious consequences because an infant’s developing brain tissue depends on a steady supply of glucose as its main source of fuel. When brain cells receive insufficient glucose, they start to die.
Risk Factors for Neonatal Hypoglycemia
There are some medical conditions that make low blood sugar levels more likely in some infants. These include:
- Babies who are small or macrosomic (large) for gestational age
- Preterm and postterm babies
- Babies who were born to diabetic mothers
- Babies who have a serious infection or who needed oxygen right after delivery
- Babies who had poor growth in the womb during pregnancy
- Babies with low thyroid hormone levels (hypothyroidism)
- Babies who have certain rare genetic disorders
Causes of Neonatal Hypoglycemia
The causes of neonatal hypoglycemia include the following:
- An excess of insulin in the baby’s blood. Insulin is a hormone that decreases the amount of glucose in the blood. This condition is called persistent hyperinsulinemic hypoglycemia of infancy (PHHI).
- Limited storage of glycogen. The stored form of glucose is called glycogen. Decreased glycogen storage can happen as a result of prematurity or intrauterine growth restriction (IUGR), and can cause hypoglycemia.
- Increased glucose use. This can happen as a result of the following medical conditions:
- Hyperthermia (high body temperature from infection, medication, or head injury)
- Polycythemia (abnormally high red blood cell mass, which can be caused by oxygen deprivation)
- Sepsis (a bacterial infection in the bloodstream)
- Growth hormone deficiency
- Decreased glycogenolysis. This is a decreased breakdown of glycogen into glucose.
- Decreased gluconeogenesis. This is a decreased creation of glucose caused by a problem with a metabolic pathway.
- Decreased use of alternate fuels. For example, an insufficient production of certain hormones.
- Depleted glycogen stores. This can be caused by the following:
- Asphyxia-perinatal stress (baby deprived of oxygen for so long during birth that damage occurs, usually to the brain.)
Long-Term Effects of Neonatal Hypoglycemia
If neonatal hypoglycemia goes undiagnosed and/or untreated for too long, there is a chance for long-term injury. Some of these injuries include:
- Brain damage
- Cerebral palsy
- Learning disabilities
- Developmental disabilities
- Epilepsy, seizures
- Vision problems
- Neuropsychiatry disorders
Signs and Symptoms of Neonatal Hypoglycemia
In many cases, infants with low blood sugar may not even show symptoms. Routine blood tests are done following birth to check blood sugar levels. If signs and symptoms do surface, they may include the following:
- Bluish-colored skin (cyanosis) or pale skin
- Breathing problems, such as rapid breathing (tachypnea), pauses in breathing (apnea), or a grunting sound
- Irritability or listlessness
- Loose or floppy muscles (hypotonia)
- Vomiting or poor feeding
- Problems keeping the body warm
- Weak or high pitched cry
- Tremors, shakiness, sweating, or seizures
Diagnosis and Treatment of Neonatal Hypoglycemia
When a baby shows clinical signs of having low blood glucose or the baby is known to be at risk for neonatal hypoglycemia, the blood glucose concentration must be determined immediately (in minutes, not hours) by sending some of the baby’s blood (usually from a warmed heel) to the lab. This is the most accurate way to measure blood glucose. However, the lab result may not be available quickly, so the method of testing glucose at the bedside with a test strip must also be used to ensure that there are no delays in diagnosing and treating the NH. Since the test strip method is less accurate, it must be verified by the lab test of the baby’s glucose.
The practical approach to treatment, and the one that is recommended by the American Academy of Pediatrics (AAP), is to identify babies who are at risk for neonatal hypoglycemia and take preventative measures to prevent the baby from having NH. The approach is to test these babies frequently, since glucose testing is not difficult. Unrecognized, persistent NH can be very dangerous and can cause irreversible brain damage.
General Treatments for Neonatal Hypoglycemia
Infants with low blood glucose levels will need to receive extra feedings with breast milk or formula. Babies who are breast-fed may need to receive supplemental formula until the mother is able to produce enough breast milk. The baby may additionally need a sugar solution (glucose) given through a vein (through an IV) if he or she is unable to feed by mouth, or if the glucose level is very low.
Treatment will be continued for a few hours or days to a week, or until the baby can maintain normal glucose levels. 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 a low glucose level continues, the baby also may receive medication to increase blood glucose levels. In very rare cases, newborns with severe hypoglycemia who don’t improve with treatment may need surgery to remove part of the pancreas. This will reduce insulin production.
Specific Treatments for Neonatal Hypoglycemia
At-risk babies should be fed by one hour of age, and their glucose level should be checked 30 minutes after the feeding. If the baby’s initial glucose level is lower than 25 mg/dL, the American Academy of Pediatrics guidelines call for feeding and checking the level again in one hour. If the level remains lower than 25 mg/dL, glucose should be given through an IV. If the level is 26 to 40 mg/dL, the guidelines call for re-feeding the baby and/or IV glucose as needed. The target glucose level is 45 mg/dL or higher before each feeding of the baby.
From four to 24 hours after birth, the baby should be fed every two to three hours, with glucose testing taking place before each feeding. If a test shows less than 35 mg/dL, the guideline is to feed and check the baby’s glucose level again in one hour. If the glucose levels remain lower than 35 mg/dL, the guidelines call for IV glucose. If the level is 35 to 45 mg/dL, the guidelines call for re-feeding with IV glucose as needed to reach the target.
The screening schedule varies slightly, depending on the baby’s condition. Late preterm (34 – 36 weeks) infants and small-for-gestational-age babies should be fed every two to three hours and screened before each feeding for at least the first 24 hours after birth. Babies born to mothers with diabetes and large-for-gestational-age infants with 34 weeks’ gestation or more should have their glucose tested for the first 12 hours after birth.
After the baby is four hours old, the goal is to achieve a glucose level of 40 to 50 mg/dL. If glucose levels are greater than 45mg/dL after 24 hours of giving the baby the recommended concentration of IV glucose, the baby may have hyperinsulinemic hypoglycemia. In these cases, an endocrinologist (a specialist who treats hormone-related problems), should be called.
At-risk infants should maintain normal glucose levels on a routine diet for at least three feeding periods before discharge.
Video: Neonatal Hypoglycemia
Legal Help for Neonatal Hypoglycemia Cases | Trusted United States Birth Injury Attorneys
Early diagnosis and treatment of neonatal hypoglycemia is crucial; the severity of the problems that can arise if neonatal hypoglycemia is left untreated highlights this point. Testing for hypoglycemia is very easy, and if the baby had any risk factors for hypoglycemia and was not tested or not tested properly for NH, the medical staff acted negligently. The medical staff also acted negligently if the baby had hypoglycemia and this condition was untreated or not treated properly. If the baby suffered brain damage or an injury as a result of these negligent acts, it is medical malpractice.
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- Adamkin DH, Committee on Fetus and Newborn. Clinical Report—Postnatal Glucose Homeostasis in Late-Preterm and Term Infants. Pediatrics. 2010-3851; published ahead of print February 28, 2011, doi:10.1542/peds.2010-3851.
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- Rozance PJ, Hay W. Hypoglycemia in newborn infants: features associated with adverse outcomes. Biol Neonate. 2006;90(2):74–86.