[Neonatal hypoglycemia]

Abstract

Background: The definition, significance, and management of neonatal hypoglycaemia and the establishment of a safe, lower limit for blood glucose concentration in the newborn is still a matter of controversy.

Methods: A review of the literature on neonatal hypoglycaemia is presented and guidelines for prevention and treatment discussed.

Results: Healthy, full-term, appropriate for gestational age infants are thought to have a better tolerance for low blood glucose values during the first days of life than later in life. The infant's brain is capable of utilizing alternative energy substrates, such as ketone bodies and lactate. Intracerebral glycogen stores in the astrocytes and increased cerebral blood flow in response to hypoglycaemia maintain a sufficient substrate delivery. Infants at risk of developing neurological impairment following hypoglycaemia have a reduced capacity for mobilizing glucose from the glycogenolysis or gluconeogenesis and for utilizing alternative substrates for energy.

Interpretation: There are no established lower limits defining neonatal hypoglycaemia of the healthy infant, but operational guidelines exist for prevention and intervention in infants at risk, for whom the blood glucose concentration should be maintained > or = 2.6 mmol/l. Very few healthy, breastfed, term infants have blood glucose levels < 2 mmol/l. It is suggested that values down to 1.7 mmol/l should be accepted as normal during the first day of life. Parenteral glucose should be administered to all infants with blood glucose levels < 1.4 mmol/l. The main goal is to prevent neonatal hypoglycaemia. Early and exclusive breastfeeding and the maintenance of normal body temperature are usually sufficient preventive measures in healthy infants.