Magnesium Sulphate Halves Risk Of Eclampsia And Can Save Lives Of Pregnant Women

Giving magnesium sulphate injections to pregnant women with pre-eclampsia halves the risk of eclampsia developing and can save their lives. This is the conclusion of a major international clinical trial funded by the Medical Research Council (MRC) and published in this week’s The Lancet.

The three-year £2.5 million study, the ‘Magpie’* Trial, was conducted in 33 countries spanning the UK and much of the developing world where eclampsia is the most common cause of death for pregnant women. The trial involved over 10,000 women.

All of the women were suffering from pre-eclampsia (pregnancy-induced high blood pressure, commonly known as toxaemia) which can lead to eclampsia (convulsions) which threatens both the mother’s and the baby’s lives.

In addition to normal medical care, half the women in the trial were randomly assigned to receive an injection of magnesium sulphate, an anticonvulsant drug. The other half was allocated a placebo treatment.

Women allocated magnesium sulphate had a 58% lower risk of eclampsia than those allocated the placebo. Although the treatment did not affect whether or not the baby died, there was evidence that it can reduce the risk of the mother dying. A quarter of women reported minor side effects but there was no evidence of harmful effects to either the mother or baby.

Dr Lelia Duley, an MRC Senior Clinical Fellow and Obstetric Epidemiologist in the Institute of Health Sciences at the University of Oxford, led the research.

She said: “Eclampsia is a devastating condition that can kill both mother and child. Our trial has shown that giving magnesium sulphate injections halves the risk of developing eclampsia for women who already have pre-eclampsia, and it seems likely it also reduces the risk of maternal death. The treatment could save countless lives across the world if it was introduced routinely for pregnant women with pre-eclampsia. And, importantly, it is a very inexpensive treatment, making it especially suitable for use in low income countries.”

Professor Jim Neilson, Professor of Obstetrics and Gynaecology at the University of Liverpool, was one of the clinicians who worked on the trial. He said: “Anticonvulsant drugs have been given to some women with pre-eclampsia for several years but this is the first time that we’ve shown clear benefits for magnesium sulphate treatment through a major research study. These exciting results should now change routine clinical practice across the UK and the world.”

Claire Giles, a woman who suffered pre-eclampsia during her first pregnancy and who took part in the trial, said: “I was really pleased to be part of such an important trial. I developed swelling at 32 weeks which grew progressively more severe until I was finally diagnosed with pre-eclampsia and admitted to hospital at 38 weeks. My baby was delivered by caesarean section and thankfully we both made a complete recovery. Pre-eclampsia is a frightening condition and I really hope that the results of the trial will benefit women like me.”

One in ten pregnant women world-wide suffers from pre-eclampsia, often in their first pregnancy. Currently the only definitive treatment is to deliver the baby early. Once the baby is born the mother’s blood pressure usually returns to normal although the baby will often require intensive medical care due to being born prematurely.

Women seeking further information about pre-eclampsia and eclampsia can call the Action on Pre-eclampsia (APEC) Helpline on 020 8427 4217 (weekdays 10am – 1pm).

The research was funded mainly by the Medical Research Council with support from the Department for International Development, the UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction and the European Commission, DG Research, INCO Programme.