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Open Access Study protocol

The Magpie Trial follow up study: outcome after discharge from hospital for women and children recruited to a trial comparing magnesium sulphate with placebo for pre-eclampsia [ISRCTN86938761]

The Magpie Trial Follow Up Study Management Group* and The Magpie Trial Follow Up Study Collaborative Group

Author Affiliations

Magpie Trial Co-ordinating Centre, Institute of Health Sciences, Old Road, Headington, Oxford OX3 7LF, UK

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BMC Pregnancy and Childbirth 2004, 4:5  doi:10.1186/1471-2393-4-5

Published: 8 March 2004



The Magpie Trial compared magnesium sulphate with placebo for women with pre-eclampsia. 10,141 women were recruited, 8804 before delivery. Overall, 9024 children were included in the analysis of outcome at discharge from hospital. Magnesium sulphate more than halved the risk of eclampsia, and probably reduced the risk of maternal death. There did not appear to be any substantive harmful effects on the baby, in the short term. It is now important to assess whether these benefits persist, and to provide adequate reassurance about longer term safety.

The main objective of the Magpie Trial Follow Up Study is to assess whether in utero exposure to magnesium sulphate has a clinically important effect on the child's chance of surviving without major neurosensory disability. Other objectives are to assess long term outcome for the mother, and to develop and assess appropriate strategies for following up large numbers of children in perinatal trials.

Study design

Follow up is only feasible in selected centres. We therefore anticipate contacting 2800–3350 families, for 2435–2915 of whom the woman was randomised before delivery. A further 280–335 children would have been eligible for follow up if they had survived. The total sample size for the children is therefore 3080–3685, 2680–3210 of whom will have been born to women randomised before delivery.

Families eligible for the follow up will be contacted, and surviving children screened using the Ages and Stages Questionnaires. Children who screen positive, and a sample of those who screen negative, will whenever possible have a paediatric and neurodevelopmental assessment. When women are contacted to ask how their child is, they will also be asked about their own health. The primary outcome is a composite measure of death or neurosensory disability for the child at 18 months.


The Follow Up Study began in 2002, and now involves collaborators in 19 countries. Data collection will close at the end of 2003.