Glucose intolerance as a consequence of oral terbutaline treatment for preterm labor

In this case series, glucose regulation is examined prospectively during treatment with terbutaline sulfate for premature labor in women who were (1) previously documented as nondiabetic, (2) found to have gestational diabetes mellitus (GDM), and (3) tested for glucose intolerance while terbutaline was being administered. The glucose profiles of women treated with terbutaline were contrasted with the profiles of nondiabetic women and women known to have GDM who were not in premature labor.

Subjects tested capillary blood glucose an average of five times a day during terbutaline treatment and for 1 week after terbutaline treatment was discontinued. They used memory-based reflectometers that stored and transmitted self-monitored blood glucose data to a personal computer.

A significant difference (P = .001) was found between average fasting glucose values (111 +/- 23 mg/dL) for the five nondiabetic subjects treated with terbutaline and values of patients in an historical control group (41 nondiabetic pregnancies [72 +/- 22 mg/dL]) who were not in premature labor. The four diabetic subjects and the one subject who had not been previously tested also experienced higher blood glucose levels during tocolytic therapy. Glucose levels returned to preintervention values with the cessation of terbutaline therapy.

It has been previously suggested that terbutaline increases hepatic glycogenolysis, which may aggravate glucose intolerance. This phenomenon, combined with normal pregnancy-induced insulin resistance, may explain abnormal ambulatory glucose patterns in women who are euglycemic before introduction of terbutaline therapy.