Is there benefit to continue magnesium sulphate postpartum in women receiving magnesium sulphate before delivery? A randomised controlled study

BJOG. 2018 Sep;125(10):1304-1311. doi: 10.1111/1471-0528.15320. Epub 2018 Jul 11.


Objective: To determine if the use of magnesium sulphate postdelivery reduces the risk of eclampsia in women with severe pre-eclampsia exposed to at least 8 hours of magnesium sulphate before delivery.

Design: Randomised multicentre controlled trial.

Setting: Latin America.

Population: Women with severe pre-eclampsia that had received a 4-g loading dose followed by 1 g per hour for 8 hours as maintenance dose before delivery.

Methods: In all, 1113 women were randomised; 555 women were randomised to continue the infusion of magnesium sulphate for 24 hours postpartum and 558 were randomised to stopping the magnesium sulphate infusion immediately after delivery.

Outcome measures: Primary outcome was the incidence of eclampsia in the first 24 hours postdelivery. Secondary outcomes included maternal death, maternal complications, time to start ambulation and time to start lactation.

Results: The maternal characteristics at randomisation between the groups were not different. There were no differences in the rate of eclampsia; 1/555 (0.18%) versus 2/558 (0.35%) [relative risk (RR 0.7, 95% CI 0.1-3.3; P = 0.50] or maternal complications between the groups (RR 1.0, 95% CI 0.8-1.2; P = 0.76). Time to start ambulation was significantly shorter in the no magnesium sulphate group (18.1 ± 10.6 versus 11.8 ± 10.8 hours; P = 0.0001) and time to start lactation was equally shorter in the no magnesium sulphate group (24.1 ± 17.1 versus 17.1 ± 16.8 hours; P = 0.0001).

Conclusions: Women with severe pre-eclampsia treated with a minimum of 8 hours of magnesium sulphate before delivery do not benefit from continuing the magnesium sulphate for 24 hours postpartum.

Tweetable abstract: No benefit of continuing magnesium sulphate postpartum in severe pre-eclampsia exposed to this drug for a minimum of 8 hours before delivery.

Keywords: magnesium sulphate; postpartum; pre-eclampsia/eclampsia.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Calcium Channel Blockers / administration & dosage
  • Calcium Channel Blockers / adverse effects
  • Delivery, Obstetric* / adverse effects
  • Delivery, Obstetric* / methods
  • Dose-Response Relationship, Drug
  • Drug Monitoring / methods
  • Female
  • Humans
  • Magnesium Sulfate* / administration & dosage
  • Magnesium Sulfate* / adverse effects
  • Obstetric Labor Complications / prevention & control*
  • Postpartum Period / drug effects
  • Pre-Eclampsia* / drug therapy
  • Pre-Eclampsia* / prevention & control
  • Pregnancy
  • Risk Assessment
  • Treatment Outcome


  • Calcium Channel Blockers
  • Magnesium Sulfate