The amount of sugar in our blood, called blood sugar or blood glucose, is the fuel that keeps all of our body systems working. If this level dips too low, it is called hypoglycemia. Low blood sugar can happen in any newborn, but some babies have a higher risk for it. Because a baby's body requires so much energy (sugar) after birth, low blood sugar usually occurs within the first few hours after birth. In general, the risk for low blood sugar in a healthy, full-term newborn declines shortly after birth. Yet, if blood sugar stays too low for too long without treatment, it can affect the brain. The effects can range from mild to severe, and may result in learning problems, vision problems and impaired development of motor skills and speech.