Neonatal hypoglycaemia in Nepal 2. Availability of alternative fuels

To study early neonatal metabolic adaptation in a hospital population of neonates in Nepal.

A cross sectional study was made of 578 neonates, 0 to 48 hours after birth, in the main maternity hospital in Kathmandu. The following clinical and nutritional variables were assessed: concentrations and age profiles of blood glucose, hydroxybutyrate, lactate, pyruvate, free fatty acids (FFA) and glycerol; associations between alternative fuel levels and hypoglycaemia; and regression of possible risk factors for ketone availability.

Risk factors for impaired metabolic adaptation were common, especially low birthweight (32%), feeding delays, and cold stress. Blood glucose and ketones rose with age, but important age effects were also found for risk factors like hypothermia, thyroid hormone activities, and feeding practices. Alternative fuel concentrations, except FFA, were significantly reduced in infants with moderate hypoglycaemia during the first 48 hours after birth. Unlike earlier studies, small for gestational age (SGA) infants had significantly higher hydroxybutyrate:glucose ratios which suggested counter regulatory ketogenesis. Hypoglycaemic infants were not hyperinsulinaemic. Regression analysis showed risk factors for impaired counter regulation which included male and large infants, hypothermia, and poorer infant thyroid function. SGA infants and those whose mothers had received no antenatal care had increased counter regulation.

Alternative fuels are important in the metabolic assessment of neonates, and they might provide effective cerebral metabolism even during moderate hypoglycaemia. Hypoglycaemic infants generally had lower concentrations of alternative fuels through either reduced availability or increased consumption. SGA and post term infants increased counter regulatory ketogenesis with early neonatal hypoglycaemia, but hypothermia, male gender, and low infant T4 were associated with impaired counter regulation after birth.