Long-term subcutaneous terbutaline tocolysis: report of possible neonatal toxicity.

Terbutaline is a beta-sympathomimetic agent that has gained wide use in obstetrics as a tocolytic agent. In addition to inhibiting uterine contractions, terbutaline can cause other clinically significant beta-mediated effects. Terbutaline readily crosses the placenta, and both fetal and neonatal toxicity have been reported. We report possible cardiovascular toxicity secondary to long-term prenatal terbutaline exposure involving three preterm infants of a quadruplet pregnancy. The infants developed cardiovascular decompensation with bradycardia, metabolic acidosis, poor tissue perfusion, and decreased urine output. The infants' conditions were resistant to all routine interventions but responded well to dobutamine infusion. We theorize that long-term prenatal beta-mimetic exposure led to downregulation of fetal beta-receptors. This resulted in impaired myocardial function, increased peripheral vascular resistance, and poor cardiac output. We suggest that neonates with a history of prenatal exposure to terbutaline should be observed closely after birth for any evidence of cardiovascular deterioration.