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.