Magnesium sulphate and other anticonvulsants for women with pre-eclampsia.
BACKGROUND
Eclampsia, the occurrence of a seizure (fit) in association with pre-eclampsia, is rare but potentially life-threatening. Magnesium sulphate is the drug of choice for treating eclampsia. This review assesses its use for preventing eclampsia.


OBJECTIVE
To assess the effects of magnesium sulphate, and other anticonvulsants, for prevention of eclampsia.


METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (4 June 2010), and the Cochrane Central Register of Controlled Trials Register (The Cochrane Library 2010, Issue 3).


METHODS
Randomised trials comparing anticonvulsants with placebo or no anticonvulsant, or comparisons of different drugs, for pre-eclampsia.


METHODS
Two authors assessed trial quality and extracted data independently.


RESULTS
We included 15 trials. Six (11,444 women) compared magnesium sulphate with placebo or no anticonvulsant: magnesium sulphate more than a halved the risk of eclampsia (risk ratio (RR) 0.41, 95% confidence interval (CI) 0.29 to 0.58; number needed to treat for an additional beneficial outcome (NNTB) 100, 95% CI 50 to 100), with a non-significant reduction in maternal death (RR 0.54, 95% CI 0.26 to 1.10) but no clear difference in serious maternal morbidity (RR 1.08, 95% CI 0.89 to 1.32). It reduced the risk of placental abruption (RR 0.64, 95% CI 0.50 to 0.83; NNTB 100, 95% CI 50 to 1000), and increased caesarean section (RR 1.05, 95% CI 1.01 to 1.10). There was no clear difference in stillbirth or neonatal death (RR 1.04, 95% CI 0.93 to 1.15). Side effects, primarily flushing, were more common with magnesium sulphate (24% versus 5%; RR 5.26, 95% CI 4.59 to 6.03; number need to treat for an additional harmful outcome (NNTH) 6, 95% CI 5 to 6).Follow-up was reported by one trial comparing magnesium sulphate with placebo: for 3375 women there was no clear difference in death (RR 1.79, 95% CI 0.71 to 4.53) or morbidity potentially related to pre-eclampsia (RR 0.84, 95% CI 0.55 to 1.26) (median follow-up 26 months); for 3283 children exposed in utero there was no clear difference in death (RR 1.02, 95% CI 0.57 to 1.84) or neurosensory disability (RR 0.77, 95% CI 0.38 to 1.58) at age 18 months.Magnesium sulphate reduced eclampsia compared to phenytoin (three trials, 2291 women; RR 0.08, 95% CI 0.01 to 0.60) and nimodipine (one trial, 1650 women; RR 0.33, 95% CI 0.14 to 0.77).


CONCLUSIONS
Magnesium sulphate more than halves the risk of eclampsia, and probably reduces maternal death. There is no clear effect on outcome after discharge from hospital. A quarter of women report side effects with magnesium sulphate.
Centre for Epidemiology and Biostatistics, University of Leeds, Bradford Institute for Health Research, Bradford Royal Infirmary, Duckworth Lane, Bradford, West Yorkshire, UK, BD9 6RJ.
Lelia
L
Duley
A Metin
AM
Gülmezoglu
David J
DJ
Henderson-Smart
Doris
D
Chou
D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use*; D004461:Eclampsia / Q000517:prevention & control; D005260:Female; D006801:Humans; D008278:Magnesium Sulfate / Q000009:adverse effects / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000188:drug therapy*; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic
D000927:Anticonvulsants; D008278:Magnesium Sulfate