Newly delivered humans have a higher risk of hypoglycemia because they are burning a lot of glucose as newly independent beings; also, they frequently have insufficient stores since the maternal-fetal "spoon-fed" supply of glucose is abruptly cut off with the interruption of the umbilical cord.

Therefore, during the normal transition to extrauterine life (at delivery), blood glucose concentration in the healthy term newborn falls during the first two hours after delivery but usually goes no lower than 40 mg/dL.

It is important to differentiate this normal physiologic transitional response from abnormal disorders that result in persistent or recurrent hypoglycemia that causes neurologic damage.

 

Causes of Neonatal Hypoglycemia

The causes of neonatal hypoglycemia fall into two categories:

DIMINISHED GLUCOSE SUPPLY:

• inadequate glycogen stores, as in preterm infants;
• impaired glucose production, as with endocrine and metabolic disorders;
• fetal growth restriction from placental problems resulting in small-for-gestational-age (SGA) newborns.

INCREASED GLUCOSE UTILIZATION:

• hyperinsulinism.

This is seen in neonates born of diabetic mothers, long used to hyperglycemia caused by their mother's high blood sugar. The neonate's higher insulin levels (maintained before birth to handle the increased load) are still there to act against the suddenly normal (and lower!) glucose levels after separation from the mother.

The result: higher insulin levels overact on less glucose than what the baby was used to handling. The blood glucose crashes.

 

How Much Hypoglycemia Is Too Much Hypoglycemia?

Although clinically significant neonatal hypoglycemia cannot be defined by some exact blood glucose number, for purposes of management strategies in the field, neonatal blood glucose should be > 70-80mg/dL, and blood glucose < 40-45 mg/dL indicates hypoglycemia.

(Again, as above, this must be differentiated from the normal transient hypoglycemia seen in the transition to extrauterine life.)

Neonatal blood sugar should be checked with all newborns, and if glucose readings are found to be < 70-80mg/dL, re-evaluations of the blood glucose should be performed every 30 minutes to 1 hour.

 

Risk for Hypoglycemia

• SGA (small-for-gestational-age);
• LGA (large-for-gestational-age);
• prematurity (<37 weeks gestation);
• infants of diabetic mothers;
• infants with perinatal stress, such as birth asphyxia, pre-eclampsia, meconium aspiration syndrome, and
• maternal hypertension in the mother

If you are attending an infant that is LGA (> 4 kg/8.8 lbs.), you should assume the mother is diabetic and obtain a blood glucose on the neonate.

There is no downside to this assumption and your reaction (getting a blood glucose)!

 

Signs and Symptoms of Hypoglycemia

Hypoglycemic neonates exhibit:

• jitteriness/tremors;
• sweating;
• irritability;
• tachypnea (rapid breathing);
• pallor or pale complexion;
• poor suck or feeding;
• weak or high-pitched cry;
• hypotonia (limp or lethargic);
• seizures;
• apnea, bradycardia, cyanosis;
• hypothermia.

When considering the above list, it is evident that there is considerable crossover between it and symptoms of hypothermia, hypoxia, bradycardia, and neonatal fever.

The bottom line always falls back onto the ABCs along with minimizing neonatal temperature loss:

►ABCs + Temp Maintenance.

 

Treatment of Neonatal Hypoglycemia

Treatment for neonatal hypoglycemia includes

• supporting the airway, breathing, and circulatory function (the "ABCs").

Also,

• glucose (D10 is the correct concentration of the drug for reversing hypoglycemia in neonates), which is established with a blood glucose of 40-45 mg/dL.

It shouldn't be given routinely (that is, without a blood sugar determination) in case the diagnosis is incorrect, risking HYPERglycemia.

♦ DOSE: D10W at 2mL/kg for blood glucose <40-45 mg/dL.

Higher concentrations can cause local tissue damage if they extravasate. It should be administered slowly at 2-3 ml/min. Giving it slowly will help avoid creating a swing to hyperglycemia, which can then cause rebound hypoglycemia, defeating its whole purpose.

• Warm IV fluids may assist in rewarming.

Environmental conditions should be kept between 75-78°F, but in the case of hypothermia, as close to the desired core temperature as possible.

• The transport facility should be equipped to handle high-risk newborns.