RT Book, Section A1 Sperling, Mark A. A1 Menon, Ram A2 Stevenson, David K. A2 Cohen, Ronald S. A2 Sunshine, Philip SR Print(0) ID 1109795410 T1 Hypoglycemia in the Newborn T2 Neonatology: Clinical Practice and Procedures YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071763769 LK accesspediatrics.mhmedical.com/content.aspx?aid=1109795410 RD 2024/04/19 AB This chapter outlines the epidemiology, etiology, pathophysiology, differential diagnosis, and management approach to the neonate with hypoglycemia, here defined as 40 mg/dL or less (≤2.2 mmol, the fifth percentile for age) during the first 2 days of life and 50 mg/dL or less (≤2.8 mmol) of whole blood glucose thereafter, with or without suggestive symptoms. Note that plasma glucose concentration is about 10%–15% greater than whole blood glucose concentration, so criteria for hypoglycemia based on plasma glucose measurements must be appropriately adjusted to be greater. Recent advances in our understanding of the biochemistry, physiology, and molecular biology regulating prenatal and postnatal glucose homeostasis combine to provide a rational basis for defining, identifying, diagnosing, and treating hypoglycemia in the newborn to enable normal neurodevelopment.1, 2 These considerations provide a systematic approach to the problem of neonatal hypoglycemia and argue for glucose measurements to become part of routine care in all neonates prior to discharge from the newborn nursery and in all sick neonates even after discharge from the newborn nursery.