Decreased fetal movements with sustained maternal hyperglycemia using the glucose clamp technique

The purpose of this study was to evaluate the effect of sustained maternal hyperglycemia (120 mg/dl) on fetal activity. The glucose infusion study group was comprised of nine healthy gravidas between 36 and 40 weeks' gestation, and six patients served as controls. The protocol design included an overnight fast for all patients. Fetal movements were evaluated by external fetal monitoring. A 2-hour preinfusion evaluation of fetal activity served as the baseline control for each patient studied. Study patients then received a glucose infusion by a glucose clamp technique to maintain a sustained hyperglycemia of 120 mg/dl for 3 hours. After the glucose infusion, fetal movements were observed for 1 hour. Control patients received a saline infusion for 2 hours after a 2-hour baseline evaluation. Maternal hyperglycemia was associated with a significant decrease of fetal movements greater than 1 second duration during the first hour of glucose infusion. Fetal movements returned to baseline during the second and third hours of glucose infusion. Saline infusion was not associated with a decrease in fetal activity. We conclude that sustained maternal hyperglycemia is associated with a transient decrease in fetal movement during the first hour of glucose infusion followed by a return to the control (preinfusion) level of fetal activity. These data may have implications in the study of fetal behavior in diabetes mellitus.