Studies

Eclampsia

[Data collection for this study is complete. Analysis in progress]

Background

Eclampsia is a rare condition associated with severe morbidity for both mother and baby. Eclampsia is defined as the occurrence of convulsions, not caused by any coincidental neurological disease such as epilepsy, in a woman whose condition also meets the diagnostic criteria for pre-eclampsia (a hypertensive disorder of pregnancy). Hypertensive disorders in pregnancy, which includes eclampsia, are known to be a major cause of maternal morbidity and mortality worldwide1 and accounted for 17% of direct maternal deaths in Australia during 2003-2005.2 Since the publication of the Collaborative Eclampsia trial3 and the Magpie trial,4 there have been major changes to the management of eclampsia, largely due to the established efficacy of magnesium sulphate in the treatment and prevention of eclampsia. The incidence of eclampsia and the associated severe morbidity is unknown in Australia. The extent to which Australian clinicians have adopted the treatment recommendations for eclampsia since publication of the major international trials is unknown. There is an urgent need to improve understanding the epidemiology of eclampsia in Australia and its treatment.

Research questions

  1. What is the incidence of eclampsia in Australia?
  2. How is eclampsia managed in Australia?
  3. What are the outcomes for mother and infant of eclampsia in Australia?
  4. Are there any risk factors that may alter the outcomes for mothers and infants in Australia?

Method

Prospective prevalence study using monthly negative surveillance system of all birthing services in Australia (>50 births) – AMOSS. Nominated clinicians and midwives within each maternity unit will be e-mailed a simple tick-box to indicate whether a case occurred or whether there is 'nothing to report'. If a case arose, the reporting clinician will complete a case form using the secure web-based data system. Only non-identifiable data will be collected.

Study period

January 2010 to December 2011

Case definition

Any woman having convulsions during pregnancy or in the first ten days postpartum, together with at least two of the following features within 24 hours of the convulsion/s:

  • Hypertension (a booking diastolic pressure of <90mmHg, a maximum diastolic of ≥ 90mmHg and/or a diastolic increment of ≥ 25mmHg)
  • Proteinuria (at least + protein in a random urine sample or ≥ 0.3g in a 24 hour collection)
  • Thrombocytopenia (platelet count of less than 100 x109/1)
  • Raised plasma alanine aminotransferase concentration (>42iu/I), or an increased plasma aspartate aminotransferase concentration (>42iu/l)5

Study size

The study period was initially planned for one year.. The estimated sample size for this period was between 68-87 cases. This is based upon the incidence found in the UK of 2.7 cases per 10,000 births (95% CI 2.4-3.1/10,000).5 However, we anticipated there may be a higher incidence in Australia given that hypertensive conditions were responsible for five deaths in 2003-2005.2

Data collection

Cases were identified through AMOSS monthly reporting. Hospitals will be asked to respond monthly whether or not there had been any women that had an eclamptic episode. Negative reporting was requested to ensure verification of nil reports and hence confirmation of the appropriate denominator used to calculate incidence.

Investigators

AMOSS CHIEF INVESTIGATORS

Professor Elizabeth Sullivan, Principal Investigator AMOSS, Professor of Public Health, Assistant Deputy Vice Chancellor, University of Technology Sydney and Conjoint Professor, UNSW Medicine, New South Wales

Professor David Ellwood, CI AMOSS, Director of Maternal-Fetal Medicine, Professor of Obstetrics & Gynaecology, Deputy Head of School Research, Gold Coast Health District, Queensland and Deputy Dean, College of Medicine, Australian National University, Australian Capital Territory

Professor Michael Peek, CI AMOSS, Associate Dean, Department of Obstetrics and Gynaecology, Medical School, College of Medicine, Biology and Environment, The Australian National University and Centenary Hospital for Women and Children, Australian Capital Territory

Professor Caroline Homer, CI AMOSS, Professor of Midwifery, Associate Dean: International and Development, Associate Head, WHO Collaborating Centre for Nursing, Midwifery and Health Development, Faculty of Health, University of Technology Sydney, New South Wales

Professor Lisa Jackson Pulver, CI AMOSS, ProVice Chancellor Engagement and Aboriginal and Torres Strait Islander Leadership, Western Sydney University, New South Wales 

Professor Marian Knight, NIHR Professor of Maternal and Child Population Health, National Perinatal Epidemiology Unit (NPEU), University of Oxford, UK.

Dr. Claire McLintock, CI AMOSS, Obstetric physician and haematologist, National Women's Health, Auckland City Hospital, New Zealand

AMOSS ASSOCIATE INVESTIGATORS

Professor Elizabeth Elliott, Professor of Paediatrics & Child Health, The University of Sydney and Australian Perinatal Statistics Unit, The Children's Hospital Westmead New South Wales

Clinical Assoc Professor Nolan McDonnell, Staff Specialist Department of Anaesthesia and Pain Medicine, King Edward Memorial Hospital for Women, Perth Western Australia

Dr Tessa Ho, Trustee, Mary Aitkenhead Ministries

Dr Wendy Pollock, Honorary Research Fellow, La Trobe University/Mercy Hospital for Women, Melbourne Victoria

Associate Professor Yvonne Zurynski, The University of Sydney and Australian Perinatal Statistics Unit, The Children's Hospital Westmead New South Wales

Funding and other support

We gratefully acknowledge our funding partners and participating AMOSS sites.

Initial funding was through a five year project grant (Australian National Health and Medical Research Council NHMRC #510298 2008-2012), which provided support for the first set of AMOSS studies as well as the AMOSS infrastructure.

The University of New South Wales provided support to redevelop the AMOSS site with a Major Research Equipment and Infrastructure Initiative (MREII) Grant in 2013.

Other funding support has been provided through the University of Technology Sydney.

Data collection is supported by AMOSS participating sites.

References

  1. Khan KS, Wojdyla D, Say L, Gulmezoglu AM, Van Look PF. WHO analysis of causes of maternal deaths: a systematic review. The Lancet 2006;367:1066- 1074.
  2. Sullivan EA, Hall B & King JF. (2007). Maternal deaths in Australia 2003- 2005. Maternal deaths series no. 3 Cat. no. PER 42. Sydney: AIHW National Perinatal Statistics Unit.
  3. The Eclampsia Trial Collaborative Group. Which anticonvulsant for women with eclampsia? Evidence from the Collaborative Eclampsia Trial. The Lancet. 1995;345:1455-1463.
  4. The Magpie Trial Group. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial. The Lancet. 2002;359:1877-1890.
  5. Knight M, on behalf of UKOSS. Eclampsia in the United Kingdom 2005. BJOG. 2007;114:1072-1078.