title: Magnesium maintenance therapy for preventing preterm birth after threatened preterm labour.
abstract: BACKGROUND
  Magnesium maintenance therapy is one of the types of tocolytic therapy used after an episode of threatened preterm labour (usually treated with an initial dose of tocolytic therapy) in an attempt to prevent the onset of further preterm contractions.
  
  
  OBJECTIVE
  To assess whether magnesium maintenance therapy is effective in preventing preterm birth after the initial threatened preterm labour is arrested.
  
  
  METHODS
  We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2013).
  
  
  METHODS
  Randomised controlled trials of magnesium therapy given to women after threatened preterm labour.
  
  
  METHODS
  The review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry.
  
  
  RESULTS
  We included four trials involving 422 women. Three trials had high risk of bias and none included any long-term follow-up of infants. No differences in the incidence of preterm birth or perinatal mortality were seen when magnesium maintenance therapy was compared with placebo or no treatment; or alternative therapies (ritodrine or terbutaline). The risk ratio (RR) for preterm birth (less than 37 weeks) for magnesium compared with placebo or no treatment was 1.05, 95% confidence interval (CI) 0.80 to 1.40 (two trials, 99 women); and 0.99, 95% CI 0.57 to 1.72 (two trials, 100 women) for magnesium compared with alternative therapies. The RR for perinatal mortality for magnesium compared with placebo or no treatment was 5.00, 95% CI 0.25 to 99.16 (one trial, 50 infants); and 5.00, 95% CI 0.25 to 99.16 (one trial, 50 infants) for magnesium compared with alternative treatments.Women taking magnesium preparations were less likely to report side effects (RR 0.67, 95% CI 0.47 to 0.96, three trials, 237 women), including palpitations or tachycardia (RR 0.26, 95% CI 0.13 to 0.52, three trials, 237 women) than women receiving alternative therapies. Women receiving magnesium were however, more likely to experience diarrhoea (RR 6.79, 95% CI 1.26 to 36.72, three trials, 237 women).
  
  
  CONCLUSIONS
  There is not enough evidence to show any difference between magnesium maintenance therapy compared with either placebo or no treatment, or alternative therapies (ritodrine or terbutaline) in preventing preterm birth after an episode of threatened preterm labour.
authors.affiliation: ARCH: Australian Research Centre for Health of Women and Babies, The Robinson Institute, Discipline of Obstetrics and Gynaecology,The University of Adelaide, Adelaide, Australia.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Han
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Crowther
authors.forename: Vivienne
authors.initials: V
authors.lastname: Moore
mesh_terms: D005260:Female; D006801:Humans; D015636:Magnesium Chloride / Q000627:therapeutic use; D017616:Magnesium Compounds / Q000627:therapeutic use*; D008277:Magnesium Oxide / Q000627:therapeutic use; D008278:Magnesium Sulfate / Q000627:therapeutic use; D007752:Obstetric Labor, Premature / Q000188:drug therapy*; D011247:Pregnancy; D047928:Premature Birth / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D012312:Ritodrine / Q000627:therapeutic use; D013726:Terbutaline / Q000627:therapeutic use; D015145:Tocolysis / Q000379:methods; D015149:Tocolytic Agents / Q000627:therapeutic use*
chemical_list: D017616:Magnesium Compounds; D015149:Tocolytic Agents; D015636:Magnesium Chloride; D008277:Magnesium Oxide; D008278:Magnesium Sulfate; D012312:Ritodrine; D013726:Terbutaline