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NSAIDs, calcium channel blockers best to delay premature delivery and improve outcomes

Clinical Question:
What is the most effective way to delay labor and improve outcomes in women at risk for preterm delivery?

Bottom Line:
Nonsteroidal antiinflammatory drugs (NSAIDs), calcium channel blockers, and magnesium sulfate are most likely to delay onset of labor in women at risk for preterm delivery. However, evidence is not strong that any tocolytic therapy results in lower neonatal mortality or respiratory distress. (LOE = 1a-)

Haas DM, Caldwell DM, Kirkpatrick P, McIntosh JJ, Welton NJ. Tocolytic therapy for preterm delivery: systematic review and network meta-analysis. BMJ 2012;345:e6226.  [PMID:23048010]

Study Design:
Meta-analysis (randomized controlled trials)


Various (meta-analysis)

The researchers used 4 databases, including the Cochrane Register, to identify all randomized trials of tocolytic therapy in women at risk of preterm delivery. Two reviewers independently selected articles for inclusion and extracted data. Studies were assessed for sources of bias and categorized as high risk, low risk, or unclear. The authors used a network meta-analysis to provide both direct and indirect comparisons of the various tocolytics. In this approach, they use complex mathematics to infer the relative effectiveness of drugs that have not been compared directly, a process used in other analyses but only recently applied to meta-analyses. Compared with placebo, NSAIDs were most likely to delay labor by 48 hours (odds ratio [OR] = 5.39) followed by magnesium sulfate (OR = 2.76), calcium channel blockers (OR = 2.71) and beta-mimetics (OR = 2.02). However, no evidence was found that any drug class decreased neonatal mortality or respiratory distress to a greater extent than placebo. Study results were not homogeneous across studies, preventing the authors from drawing other conclusions.


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