Efficacy of maintenance therapy after acute tocolysis: a meta-analysis

Our purpose was to analyze published randomized trials assessing the efficacy of maintenance tocolytic therapy after short-term tocolysis in patients with acute preterm labor.

We supplemented a search of entries in electronic databases with references cited in original studies and review articles to identify randomized trials assessing the efficacy of maintenance tocolytic therapy after resolution of the acute preterm labor episode. Two masked investigators performed independent trial quality evaluation and data abstraction of each trial. We calculated an estimate of the odds ratio and risk difference for dichotomous outcomes, using both a random- and fixed-effects model. Continuous outcomes were pooled with a variance-weighted average of the within-study difference in means.

Of 17 studies identified, 12 met our criteria for meta-analysis. These 12 trials included 1590 patients, including 855 who received maintenance tocolysis and 735 comparison patients who received placebo or no maintenance treatment. Compared with placebo or no treatment, the pooled odds ratio for preventing preterm delivery was 0.95 (95% confidence interval, 0. 77-1.17), and the odds ratio for preventing recurrent preterm labor was 0.81 (95% confidence interval, 0.64-1.03). In addition, use of maintenance tocolytic therapy was not associated with decreased rates of neonatal respiratory distress syndrome, perinatal deaths, or differences in birth weight. Although no difference was noted in mean gestational age at delivery, those receiving tocolytic agents had a longer latency period.

Maintenance tocolytic therapy after successful treatment of an acute episode of preterm labor does not reduce the incidence of recurrent preterm labor or preterm delivery and does not improve perinatal outcome. Accordingly, the results of this meta-analysis do not support the use of maintenance tocolytic therapy after successful treatment of preterm labor.