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Evevident
Original paper
2002LancetOB/GYN

MAGPIE

Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial

RCTPreeclampsia

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Overview

Magnesium sulfate roughly halved eclampsia risk in women with preeclampsia.

Clinical takeaway

MAGPIE established magnesium sulfate as the standard seizure-prevention therapy for preeclampsia, especially severe disease.

Key result

Eclampsia was reduced by about 58% with magnesium sulfate.

Practice impact

Magnesium sulfate became routine prophylaxis for severe preeclampsia and treatment/prevention around eclampsia.

Evidence

Study design

Large randomized, placebo-controlled trial.

Enrollment

10,141

Follow-up

Until hospital discharge for main maternal outcomes.

Geography

Multinational

Clinical question

Does magnesium sulfate prevent eclampsia and improve outcomes in women with preeclampsia?

Population

  • Pregnant or recently delivered women with preeclampsia for whom there was clinical uncertainty about magnesium sulfate.

Intervention

Magnesium sulfate regimen.

Comparator

Placebo.

Primary outcome

Eclampsia and maternal death/serious morbidity outcomes.

Magnesium sulfate substantially reduced the risk of eclampsia among women with preeclampsia.

Relative risk / 0.42 / CI 95% CI 0.29-0.60

Key results

  • Eclampsia was substantially reduced with magnesium sulfate.
  • Maternal death was lower but uncommon.
  • Side effects such as flushing were more common, but serious toxicity was uncommon with monitoring.

Harms

  • Flushing and other minor side effects were common.
  • Respiratory depression and loss of reflexes are toxicity concerns requiring monitoring.

Clinical Use

When to cite

  • When starting magnesium sulfate for preeclampsia with severe features or eclampsia prevention.

Practice impact

  • Made magnesium sulfate standard for seizure prophylaxis in severe preeclampsia and treatment of eclampsia.

Applicability

  • Women with preeclampsia, especially severe features or high seizure risk.

Limitations

  • Absolute benefit varies by baseline eclampsia risk.
  • Requires clinical monitoring, reflex checks, respiratory assessment, and renal-dose awareness.

Common misinterpretations

  • Magnesium prevents seizures; it is not an antihypertensive treatment for severe-range blood pressure.

Related evidence

CHAP - Same DiseaseASPRE - Context

Citation

Altman D, Carroli G, Duley L, et al. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial. Lancet. 2002;359(9321):1877-1890. doi:10.1016/s0140-6736(02)08778-0

Magnesium sulphate halves the risk of eclampsia, and probably reduces the risk of maternal death.