Effects of Terbutaline, a Selective β_2-Receptor Agonist, on Uterine Contraction and Maternal or Fetal Circulatory System in Pregnant Rabbits

The effects of terbutaline, a selective β_2-adrenergic receptor stimulant, on the uterine activity were studied in near-term pregnant rabbits. Terbutaline with infusion rates of 1.33 and 2.66 μg/ml significantly suppressed spontaneous uterine activities. There were no significant changes in maternal heart rate, blood pressure, PO_2 or PCO_2 by the infusion of terbutaline. No ominous fetal heart rate pattern was observed during the infusion of terbutaline. It was concluded that in the rabbit, terbutaline would be an effective tocolytic agent with minimal untoward effects on maternal and fetal circulating systems.