Successful magnesium sulfate tocolysis: is “weaning” the drug necessary

Magnesium maintenance therapy for preventing preterm birth after threatened preterm labour

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.

OBJECTIVES

To assess whether magnesium maintenance therapy is effective in preventing preterm birth after the initial threatened preterm labour is arrested.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2013).

SELECTION CRITERIA

Randomised controlled trials of magnesium therapy given to women after threatened preterm labour.

DATA COLLECTION AND ANALYSIS

The review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry.

MAIN 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).

AUTHORS' 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.

Magnesium maintenance therapy for preventing preterm birth after threatened preterm labour

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.

OBJECTIVES

To assess whether magnesium maintenance therapy is effective in preventing preterm birth after the initial threatened preterm labour is arrested.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2010).

SELECTION CRITERIA

Randomised controlled trials of magnesium therapy given to women after threatened preterm labour.

DATA COLLECTION AND ANALYSIS

The review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry.

MAIN RESULTS

We included four trials, which recruited 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 (2 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 also compared with alternative treatments, was 5.00, 95% CI 0.25 to 99.16 (one trial, 50 infants). Women taking magnesium preparations were less likely to report palpitations or tachycardia than women receiving alternative therapies (RR 0.26, 95% CI 0.13 to 0.52, three trials, 237 women) but were much more likely to experience diarrhoea (RR 7.66, 95% CI 2.18 to 26.98, three trials, 237 women).

AUTHORS' 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.

Magnesium for preventing preterm birth after threatened preterm labour

BACKGROUND

Magnesium therapy is sometimes continued after an episode of threatened preterm labour in an attempt to prevent the onset of further preterm contractions.

OBJECTIVES

The objective of this review was to assess the effects of magnesium maintenance therapy on preventing preterm birth after threatened preterm labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register.

SELECTION CRITERIA

Randomised controlled trials of magnesium therapy given to women after threatened preterm labour.

DATA COLLECTION AND ANALYSIS

Trial quality assessment and data extraction were done independently by two reviewers.

MAIN RESULTS

Two trials were included. Both were of poor quality and neither study included any long-term follow up of infants. The incidence of preterm birth or perinatal mortality was not reduced by magnesium maintenance therapy compared to alternative therapy or no treatment.

REVIEWER'S CONCLUSIONS

There is not enough evidence to show that magnesium maintenance therapy is effective in preventing preterm birth after an episode of threatened preterm labour.