Magpie Trial Follow-Up Study Collaborative Group BJOG 2007; 114 (3): 289-99 doi:10.1111/j.1471-0528.2006.01165.x.
In this large multicentre trial, 4,483 children were followed up to 18 months of age from a randomised trial of magnesium sulphate versus placebo in pregnancy for pre-eclampsia, to look at morbidity, mortality and neurodevelopment of the children exposed to magnesium in utero.
Magnesium sulphate is used worldwide for seizure therapy and prophylaxis in women with eclampsia and pre-eclampsia. Magnesium may act by opposing calcium-dependent arterial constriction and may also antagonize the increase in intracellular calcium concentration.
This is the first well-designed trial with enough children to look at the long-term consequences for the child of treating the mother with magnesium.
This group published the data on the women themselves in BJOG the month before this study and showed that the reduction in the risk of eclampsia following prophylaxis with magnesium sulphate was not associated with an excess of death or disability for the women after two years.
It also reminds us how serious eclampsia is: 58 of 1,650 (3.5 per cent) women allocated magnesium sulphate died or had serious morbidity potentially related to pre-eclampsia, compared with 72 of 1,725 (4.2 per cent) women allocated placebo (RR 0.84, 95% CI 0.60-1.18).
In the children exposed in utero to magnesium, 245 of 1,635 (15.0 per cent) were dead or had neurosensory disability at 18 months, compared with 233 of 1,648 (14.1 per cent) allocated placebo (RR 1.06, 95% CI 0.90-1.25), and of survivors, 19 of 1,409 (1.3 per cent) had neurosensory disability at 18 months, compared with 27 of 1,442 (1.9 per cent; RR 0.72, 95% CI 0.40-1.29).
The conclusion is that exposure to magnesium in utero gives no significant difference in death rates or disabilities for the child, at least up to 18 months of age. This is very reassuring for clinicians and patients alike.
- Dr Sally Hope is a GP in Woodstock, Oxfordshire, and honorary research fellow in women's health, department of primary health care, University of Oxford.