What is a normal blood sugar level?

The normal range of newborn blood sugars continues to be debated. Surveys and experience have revealed blood sugars often below 40 mg/dl (2.2 mM), rarely below 30 mg/dl (1.7 mM), in apparently healthy full-term infants on the first day of life. It has been proposed that newborn brains are able to use alternate fuels when glucose levels are low more readily than adults. Experts continue to debate the significance and risk of such levels, though the trend has been to recommend maintenance of glucose levels above 60-70 mg/dl after the first day of life. In ill, undersized, or premature newborns, low blood sugars are even more common, but there is a consensus that sugars should be maintained at least above 50 mg/dl (2.8 mM) in such circumstances. Some experts advocate 70 mg/dl as a therapeutic target, especially in circumstances such as hyperinsulinism where alternate fuels may be less available.