Table 1

Summary of findings on whether clinicians should use magnesium sulphate to prevent eclampsia: clinical outcomes

OutcomeSeverity of pre-eclampsiaTypical control group riskTypical absolute effect (95% CI)Relative risk (95% CI)No of participants Quality of evidence
EclampsiaSevere*27/100016 fewer/1000 (11 to 19)0.41 (0.29 to 0.58)11 444High†
Not severe15/10009 fewer/1000 (6 to 11)
Maternal deathSevere6/10003 fewer/1000 (0.6 more to 4 fewer)0.54 (0.26 to 1.10)10 795Moderate‡
Not severe3/10001 fewer/1000 (0.3 more to 2 fewer)
Side effects§Severe and not severe46/1000196 more/1000 (165 to 231)5.26 (4.59 to 6.03)9992High†

*Severe eclampsia was defined as (diastolic blood pressure >110 mm Hg on two occasions, or systolic blood pressure >170 mm Hg on two occasions and proteinuria >3+) or (diastolic blood pressure >100 mm Hg on two occasions, or systolic blood pressure >150 mm Hg on two occasions and proteinuria >2+ and at least two signs or symptoms of imminent eclampsia) or for women who had an antihypertensive in the 48 h before randomisation: (in 48 h before trial entry, highest diastolic blood pressure >110 mm Hg, or highest systolic blood pressure >170 mm Hg and proteinuria >3+ at trial entry) or (in 48 h before trial entry, highest diastolic blood pressure >100 mm Hg, or highest systolic blood pressure >150 mm Hg and proteinuria >2+ and at least two signs or symptoms of imminent eclampsia).

†Evidence comes from randomised trials and there was no reason to grade down for study limitations, imprecision, inconsistency, indirectness, or publication bias.

‡The confidence interval was wide so the evidence was graded down for imprecision.

§Mostly flushing. Other side effects include nausea, vomiting, slurred speech, muscle weakness, dizziness, drowsiness, confusion, and headache.