Maternal metabolic alterations secondary to terbutaline therapy for premature labor

The metabolic changes in pregnant patients treated with subcutaneous terbutaline for premature labor were studied. Arterial lactic acid, serum electrolyte, and glucose concentrations were measured in 29 patients. Samples were obtained before and 1 hour after the initial dose of terbutaline. Data included statistically significant changes in arterial pH and lactate levels and in serum glucose and potassium. In all patients tested, lactic acid and glucose concentrations increased and the potassium level significantly decreased. An increase occurred in the mean insulin level of 6 patients. It was therefore concluded that significant metabolic alterations occur in normal pregnant patients undergoing subcutaneous terbutaline treatment for premature labor. Hypokalemia, hyperglycemia, and an increase in lactic acid occur and, although these changes are handled readily and corrected rapidly in the normal pregnant patient, all patients, especially those with underlying metabolic alterations or cardiac disease, should have baseline electrolyte and glucose levels evaluated before consideration of terbutaline therapy for premature labor.