The present and future of tocolysis

This chapter discusses the tocolytic agents currently in use for the treatment of preterm labour and considers them in light of the evidence base. These agents are the β2 sympathomimetic agonists, magnesium sulphate (MgSO4), indomethacin, nifedipine and atosiban.The available evidence for these agents shows that the β2 agents are effective but have significant maternal side effects and no effect on perinatal outcome. MgSO4 and glyceryl trinitrate are clearly ineffective. Nifedipine is effective with a low maternal side effect profile and is associated with improved perinatal outcomes. Meta-analyses of the several randomized controlled trials of atosiban show that it is no more effective than other tocolytic therapies. Possible directions for the future will be discussed.