Insulin requirements during labor: a reappraisal

Continuous insulin infusion has been advocated for strict glucose control during labor in insulin-requiring diabetic patients. We studied 33 insulin-dependent diabetic patients who were at term and undergoing induction of labor with oxytocin. Each patient received a glucose infusion (6 gm/hr), and the blood glucose level was determined hourly. Blood glucose levels did not rise above 100 mg/dl in 16 patients (48.4%) despite continuous intravenous glucose infusion. No differences were found in the following parameters between these patients and those requiring insulin infusion: maternal age, weight, diabetic class, gravidity, and prior insulin requirement. Birth weights and the incidence of neonatal morbidity were similar between groups and occurred despite euglycemia during labor. We found that euglycemia during labor did not prevent infant morbidity irrespective of the use of continuous low-dose insulin infusion. Additionally, 48% of patients did not require any insulin during induction of labor despite large antenatal insulin requirements.