Metabolic effects of intravenous ritodrine infusion during pregnancy.

The effect of intravenous administration of ritodrine on blood glucose, insulin, free fatty acids and electrolytes in 17 third-trimester gravidas was investigated. A highly significant increase in blood glucose, insulin and free fatty acids and a marked decrease in serum potassium levels were registered. No significant changes during ritodrine infusion were recorded in serum levels of sodium, chloride, calcium, phosphorus and magnesium. No cardiac arrhythmias or electrocardiographic deteriorations occurred. While intravenous ritodrine administration seems to be safe in normal pregnancy, there may be a risk in diabetic patients, digitalized cases and those patients being treated with diuretics.