Although all currently available tocolytic agents perform better than placebo at delaying delivery before 32 weeks' gestation, prostaglandin inhibitors are superior.
Although all currently available tocolytic agents perform better than placebo at delaying delivery before 32 weeks' gestation for both 2 and 7 days, prostaglandin inhibitors are superior, providing the best combination of tolerance and effectiveness. Calcium channel blockers, however, may be superior for delaying delivery until 37 weeks' gestation.
Researchers from Indiana conducted a meta-analysis, which included 58 randomized controlled trials. In terms of delaying delivery for 48 hours, tocolytics were effective 75% to 93% of the time, versus 53% for placebo. For delaying delivery 7 days, tocolytics were effective 61% to 78% of the time, versus 39% for placebo. The authors of the meta-analysis calculated that 80 out of 1,000 women receiving prostaglandin inhibitors would deliver within 48 hours, versus 182 to 416 out of 1,000 for alternative agents.
The studies revealed no significant differences in the incidence of respiratory distress syndrome or neonatal death.