Glucose Homeostasis and the Neonatal Brain: A Sweet Relationship

Glucose is the primary substrate for energy metabolism in the brain and although the brain is dependent on a constant glucose supply for normal function, both local energy stores and the supply of alternate substrates are limited. In utero, the placenta provides a continuous supply of glucose to the fetus while transition to extrauterine life marks an abrupt change in substrate delivery and a major change in glucose metabolism where insufficiencies and disruptions can occur. Hypoglycemia is one of the most common biochemical disturbances in the neonatal period, affecting a wide range of neonates. Prolonged or persistent low plasma glucose concentrations can lead to neonatal brain injury and abnormal neurological outcomes. This article discusses fetal and neonatal metabolic adaptation, the physiology of glucose homeostasis, hypoglycemic brain injury (HBI), and neurodevelopmental long-term outcomes.