Serial serum potassium and glucose levels during treatment of premature labor with oral terbutaline.

The effects of prolonged use of orally-administered terbutaline on mothers and their infants were studied. The only side effect observed in all patients was transient maternal tachycardia. Fifty-six percent of the patients experienced palpitations, nervousness and tremors during the first few days of therapy, which thereafter resolved. This is contrary to the serious side effects reported during intravenous infusion of beta-mimetic agents. Maternal serum potassium and plasma glucose levels remained in the normal range during the entire therapy. Neonatal apgar, birthweight and metabolic parameters were all appropriate for gestational age. It appears that orally-administered terbutaline produces no significant maternal biochemical or biophysical changes, or any side effects on the fetus.