Use of anticonvulsants in eclampsia and pre-eclampsia: survey of obstetricians in the United Kingdom and Republic of Ireland

BMJ 1998; 316 doi: (Published 28 March 1998) Cite this as: BMJ 1998;316:975
  1. A Metin Gülmezoglu (mgulmezoglu{at}, research fellow,
  2. Lelia Duley, senior research fellow
  1. National Perinatal Epidemiology Unit, Radcliffe Infirmary, Oxford OX2 6HE
  1. Correspondence to: Dr A M Gülmezoglu, United Kingdom Cochrane Centre, NHS Research and Development Programme, Summertown Pavilion, Oxford OX2 7LG
  • Accepted 5 August 1997

Pre-eclampsia is a multisystem disorder associated with hypertension and proteinuria and is a fairly common complication of pregnancy. Eclampsia, the occurrence of fits with pre-eclampsia, is rare, but both conditions can have serious consequences for the mother and infant. Anticonvulsants are given to women with eclampsia to prevent further fits and to women with pre-eclampsia to prevent the first fit, thereby improving the outcome for mother and infant. Clinical practice, however, varies greatly worldwide. In the United Kingdom diazepam has been popular since the 1970s and phenytoin since the early 1990s, but the use of magnesium sulphate remains uncommon. 1 2 Magnesium sulphate has been widely used for decades in the United States and has recently been acknowledged as the preferred anticonvulsant for women with eclampsia.3 There is little evidence to support or refute the use of anticonvulsants in women with pre-eclampsia.4 We conducted a survey to determine the current use of anticonvulsants in eclampsia and pre-eclampsia.

Subjects, methods, and results

A questionnaire was sent to consultants in the United Kingdom and the Republic of Ireland asking about their use of anticonvulsants in women with eclampsia or pre-eclampsia. Two reminders were sent six weeks apart.

The table summarises the main results. Of the 662 respondents who used prophylactic anticonvulsants, 658 were more likely to prescribe them in the presence of signs or symptoms of imminent eclampsia and 364 would consider using an anticonvulsant if delivery was unlikely within the next 24 hours. Over half (475) of the respondents would collaborate in a placebo controlled trial of magnesium sulphate versus placebo in women with pre-eclampsia.

Anticonvulsants used by 860* obstetricians to treat pre-eclampsia and eclampsia

View this table:


Compared with earlier surveys, 1 2 our survey was shorter and simpler and focused largely on anticonvulsant use. Our survey also had a slightly better response rate (table). Since 1991, when the last survey was conducted,2 the reported use of magnesium sulphate in pre-eclampsia has risen from 2% to 40%. During 1992 only 2% of women with eclampsia received magnesium sulphate,5 whereas 60% of respondents in our survey said that they would now use this anticonvulsant for such women. As the use of magnesium sulphate had remained at 2% for 14 years,2 this change probably occurred after publication of evidence showing that magnesium sulphate is better than diazepam or phenytoin for eclampsia.3 Despite this substantial shift in practice, diazepam remains the most widely used anticonvulsant for pre-eclampsia and eclampsia, and phenytoin continues to be used by a quarter of respondents. We believe that magnesium sulphate should be used in preference to diazepam and phenytoin.

Uncertainty about the role and choice of prophylactic anticonvulsant treatment for pre-eclampsia is reflected in the variation in clinical practice. For example, an increasing proportion of obstetricians never use prophylactic anticonvulsants (16% in 1991 v 23% in 1996).2 Among those who do there is no consensus on which agent to use or when prophylaxis is appropriate (data not shown). One aim of our survey was to assess the feasibility of conducting a multicentre, randomised, placebo controlled trial of magnesium sulphate versus placebo in women with pre-eclampsia. Over half of the respondents indicated their interest in collaborating in such a study compared with only 3% of respondents in the 1991 survey.2 This confirms the increased uncertainty about the role of anticonvulsants in women with pre-eclampsia.


We thank the respondents to our questionnaire.

Contributors: LD had the original idea and participated in the design and conduct of the study. AMG participated in the design and conduct of the study and was responsible for coordination. Both authors supervised the analysis and wrote the paper and will act as guarantors for the paper. Sarah Ayers provided programming support and Caroline Busby entered the data.

Funding: This study was funded by a grant from the Department for International Development; it does not take any responsibility for the contents of this article.

Conflict of interest: None.


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