New systematic review shows that early warning systems are effective in improving outcomes for pregnant women

News article 6 Jun 2019

Early Warning Systems (EWS) are used in medicine as a way of identifying a potential problem ahead of time. This enables healthcare providers to make informed decisions and take corrective action to avoid or reduce the impact of that problem. EWS combine clinical observations such as vital signs (eg Respiratory rate/blood pressure/heart rate), clinical examination findings and laboratory tests to identify a pattern that is consistent with an increased risk of a patient deteriorating clinically. When a patient’s records match this pattern, this is flagged to healthcare providers who implement an action plan as soon as possible.

It has been recommended that modified early warning systems are used for pregnant women as a timely way to detect any clinical problems throughout pregnancy and childbirth. This has been actively promoted in the UK since the 2005 Confidential Enquiry into Maternal Deaths. It is thought that using obstetric EWS could also positively impact on maternal morbidity and mortality in low-resource countries. However, there is not much evidence on its feasibility in these settings.

Researchers from the Centre for Maternal and Newborn Health (CMNH) conducted a systematic review to:

  • synthesise the evidence on the effectiveness of obstetric EWS as screening tools for predicting morbidity (ill health) and mortality (death)
  • determine the effectiveness of the EWS in improving clinical outcomes
  • explore the feasibility of EWS implementation in low resource settings.

Their review has been published in the journal PLOS One: Early warning systems in obstetrics: A systematic literature review

The CMNH review concludes that obstetric early warning systems are effective in predicting severe morbidity in general obstetric populations. It shows that they may improve the frequency of how often routine vital sign observations are conducted and may reduce the interval between when patients deteriorate and when corrective clinical action is taken. This can potentially improve the quality of care and reduce the risk of adverse obstetric outcomes for pregnant women and those who have just given birth.

This review also shows that early warning systems are highly accurate in predicting maternal death among critically ill obstetric patients. However, there is limited evidence of their effectiveness in reducing maternal deaths. More robust studies are now needed to assess their effectiveness.

Encouragingly, the review also concluded that because most obstetric EWS versions are based on basic clinical observations that can be routinely collected in resource-limited settings, they are feasible to use in such settings.

Dr Charles Ameh, Senior Lecturer at the Centre for Maternal and Newborn Health and corresponding author on this paper:
I believe that obstetric EWS have a role in the fight to end preventable maternal mortality in low-resource settings, if properly developed and validated. I look forward to our next publication on the development and validation of an obstetric EWS for resource limited settings’

Hypothesis of the early warning system intervention