The normal value of blood glucose in newborns is between 2.6-6.5 mmol/L. If it is calculated by mg/dL, a newborn with a blood glucose level <2.2 mmol/L or 40 mg/dL is diagnosed as hypoglycemia. If the blood glucose value is between 2.2-2.6mmol/L, early intervention is required, so the indicator for diagnosing hypoglycemia is blood glucose <2.2mmol/L. If the blood glucose is <2.6mmol/L, early intervention should be started to prevent the occurrence of hypoglycemic encephalopathy. Because brain damage caused by hypoglycemia is irreversible, if the blood glucose measured one hour after the opening of milk is lower than 2.2mmol/L in clinical practice, it should be actively treated to avoid brain damage.