Acute Tocolysis Research Articles

The 29th Annual Meeting of SOAP

The 29th Annual Meeting of SOAP

Evidence for magnesium sulfate as a tocolytic agent.

The objective of our study is to quantitatively examine the available evidence regarding the efficacy and side effects of magnesium sulfate for acute tocolysis (from randomized trials) compared with placebo and beta-agonist agents. Randomized trials comparing magnesium sulfate with placebo or beta-agonists for tocolysis were identified with a MEDLINE-based search and was supplemented by a search of obstetrical textbooks and bibliographies. Trials underwent quality evaluation and data abstraction by two independent, blinded investigators. Outcomes evaluated included delivery delay of various durations as well as the frequency of major and minor side effects. Summary odds ratios and 95 percent confidence intervals for dichotomous outcomes were calculated using a random effects model. Interstudy heterogeneity for these outcomes was assessed with a Q statistic. We identified 12 randomized controlled trials of magnesium sulfate for acute tocolysis. Four studies were excluded because of either lack of comparison of magnesium sulfate to either placebo or beta-agonists or lack of reporting clinical outcomes of interest. The eight remaining randomized trials comparing magnesium sulfate with placebo or beta-agonists were included in this analysis. There was no significant difference between MgSO4 and placebo for any of the measured outcomes for delay in delivery. Comparing magnesium sulfate to ritodrine or beta-agonists did not demonstrate any differences between the agents in achieving clinically significant tocolysis. There was a significant difference between MgSO4 and beta-agonists in the frequency of medication discontinuation because of side effects, but not in the frequency of major adverse drug events. There are few data comparing magnesium sulfate with a placebo for acute tocolysis. Magnesium sulfate seems to be comparable to ritodrine and beta-agonists, although the available data are not sufficient for a rational choice between these agents.

Ketorolac is a safe and effective drug for acute tocolysis

Ketorolac is a safe and effective drug for acute tocolysis

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.

Acute Tocolysis for Fetal Distress

Summary: Forty-six women in active labour who developed fetal distress requiring abdominal delivery were randomized to receive 0.25 mg of terbutaline (subcutaneously) or magnesium sulphate as a 4-g bolus (intravenously) to decrease uterine activity. The terbutaline-treated group in contrast to the magnesium sulphate-treated group had reduced uterine activity as measured by Montevideo units (p <0.002). This decrease in uterine activity was noted more rapidly in all 23 patients who received terbutaline, 1.8 ±0.74 minutes compared to 7.5 ±2.1 minutes in the 16 of 23 patients (magnesium sulphate-treated women) in whom a decrease in uterine activity occurred (p <0.001). Umbilical cord arterial blood pH at delivery was less than 7.20 in only 2 of the 23 patients treated with terbutaline versus 7 of the 23 in the magnesium sulphate-treated group. We conclude that terbutaline is an effective and more rapid-acting tocolytic agent to arrest uterine activity prior to delivery for fetal distress.