Acute tocolysis for suspected intrapartum fetal distress: maternal effects of terbutaline versus magnesium sulfate

This study was undertaken to determine the maternal hemodynamic impact of terbutaline versus magnesium sulfate in the acute treatment of fetal distress prior to cesarean delivery. Forty-six women were prospectively randomized to receive 0.25 mg subcutaneous terbutaline or 4.0 g intravenous magnesium sulfate for in utero fetal resuscitation before cesarean delivery. There were no significant differences between groups in baseline mean arterial pressure, arterial pressure before and after induction of anesthesia, maternal heart rate, maternal oxygen saturation, estimated blood loss, and pre- and postoperative hematocrits. Magnesium sulfate-treated women received significantly more intraoperative intravenous fluids (2365 ± 877 ml) than the terbutaline group (1624 ± 564 ml; P < 0.001). However, mean urine output was significantly greater in the terbutaline group (88 ± 42 ml/h) than in those treated with magnesium sulfate (61 ± 26 ml/h; P < 0.03). Terbutaline, the superior agent for acute tocolysis, is not associated with an increase in maternal cardiovascular side effects during anesthesia.