Effects of intrapartum maternal glucose infusion on the normal fetus and newborn.

The effect of maternal intravenous glucose infusion on the newborn's glucose, insulin, and neurobehavioral performance was studied prospectively in 56 normal mother-newborn pairs. Maternal blood glucose levels at the time of delivery, umbilical venous blood glucose and insulin levels, and neonatal blood glucose levels were measured. Neurobehavioral assessment of the newborns was performed at 4 and 24 hours of life. The median value for total amount of glucose infused to the mother was 32.5 g, the median rate of glucose infusion was 8 g/h, and the median maternal blood glucose concentration at delivery was 110 mg/dl. Median umbilical venous blood glucose concentrations were 104 mg/dl and median insulin concentration was 15 microunits/ml. Six babies were hypoglycemic at 1 hour of age. Umbilical venous glucose and insulin levels correlated significantly (p less than 0.001) with the rate of glucose infusion to the mother and her blood glucose level. The incidence of neonatal hypoglycemia was significantly related (p less than 0.05) to a maternal blood glucose level greater than 120 mg/dl, to a glucose infusion rate of 20 g/hr or greater and to an umbilical venous insulin level of greater than 40 microunits/ml. There were no major differences in neurobehavior that distinguished hypoglycemic neonates. It is recommended that the normal parturient be given less than 20 g/hr of intravenous glucose before delivery and have a blood glucose level less than 120 mg/dl at the time of delivery. Newborns delivered to mothers with hyperglycemia or excessive glucose infusion should be tested for hypoglycemia at 1 and 2 hours of age.