Hypoglycemia: what is it for the neonate?

The definition of hypoglycemia in the newborn infant has remained controversial because of lack of significant correlation between plasma glucose concentration, clinical symptoms, and long-term sequelae. A threshold value for plasma glucose at which clinical intervention should be considered is important because of the potential for serious neurological injury. In this review, we have described threshold values for plasma glucose in the newborn infant, based upon available data, at which the clinician should consider close monitoring and therapeutic interventions aimed at increasing the glucose level. In clinically symptomatic infants, plasma glucose concentrations of 45 mg/dL (2.5 mmol/L) or less should be considered as threshold for intervention. In an asymptomatic baby and in those at risk for hypoglycemia, irrespective of gestational and postnatal age, plasma glucose values less than 36 mg/dL (2.0 mmol/L) should be considered as threshold levels. Variances from these criteria, as in breast-fed infants, are discussed. The threshold values described for surveillance and intervention should be separated from the targeted therapeutic values which should be in the range of 72-90 mg/dL (4-5 mmol/L).