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New Maternity Early Warning Score to be implemented in the NHS

Published: 21 May 2024

Researchers funded by the NIHR have developed a new, standardised tool to help identify and respond to signs of deterioration in the health of pregnant women.

The new “maternity early warning score” is based on patient data and is set to be rolled out across the country. 

Maternity Early Warning Scores

Maternity Early Warning Scores (MEWS) are widely used throughout hospitals in the UK to highlight when additional care is needed to protect the health of the expectant mother and baby. Their implementation varies widely across the country, and the majority of MEWS have been developed by clinical consensus.

For this study, researchers funded by the NIHR’s Oxford Biomedical Research Centre identified the need to create a standardised MEWS that could be rolled out nationally.

The study

The Pregnancy Physiology Pattern Prediction (4P) prospective UK cohort study collected data from 1,041 women during their pregnancies including:

  • blood pressure
  • heart rate 
  • respiratory rate
  • temperature
  • oxygen levels

The researchers used statistics to determine appropriate thresholds for each vital sign. These thresholds were then used to assign numerical scores, with higher scores indicating more concerning vital sign measurements.

The clinical response to higher scores was developed by 30 midwives, doctors and other experts. The researchers used a consensus exercise which allowed experts to reconsider their opinions based on the anonymised opinions of others. This ensures that the new national MEWS not only identifies potential problems, but also provides clear guidance on the appropriate escalation of care.

National rollout

The resulting new MEWS is more accurate than the current tools, and will generate fewer false alerts. The new approach is being rolled out across the NHS in England and will help staff identify and respond to signs of deterioration in pregnant women. The paper version of the tool has been implemented in 16 units across the country. A digital version is nearly complete. 

The aim is that every organisation will have implemented MEWS across England by March 2026.

Minister for Women’s Health Strategy, Maria Caulfield said: “This research is crucial to supporting our aim to provide safe and compassionate care to all women in maternity services. The new system will result in fewer false alarms and provide better care for mums and mums-to-be.

“This supports our ongoing work to improve maternity care, backed by an additional £186 million a year to improve maternity and neonatal care, on top of a further £35 million to further improve safety.”

Professor Helen McShane, Director of the NIHR Oxford BRC said: “It is wonderful to see that our BRC’s support for the 4P study has resulted in a system that will deliver more consistent and targeted help during and just after pregnancy. This is the essence of what we do – taking scientific advances and translating it into improvements for NHS patients. I look forward to seeing this MEWS rolled out across the NHS in England.”

Professor Marian Knight, NIHR Scientific Director for Research Infrastructure, said: “This research shows the huge value of NIHR-funded infrastructure such as the Biomedical Research Centres. Conducting the early phases of this work to determine the normal ranges of measurements for pregnant women within the Oxford BRC has then allowed us to work with colleagues in NHS England to develop a system to give us better warning of when pregnant women are becoming sick and roll it out across the NHS. Further NIHR funded work will then allow us to take this further and develop a tool which will specifically help to tackle maternity inequalities.”

Further NIHR funding into maternal health 

Pregnant women and mothers from less wealthy areas and particular ethnic groups are more likely to come to harm. In May 2023 the NIHR funded a £2.68m study to find out whether an electronically-embedded, data-enhanced Modified Obstetric Early Warning Score (eMOEWS) can prevent maternal near-miss and severe morbidity events, and reduce inequalities in outcomes. 

And in March 2024 NIHR announced the first ever NIHR Challenge funding call, backed by £50m. It has tasked researchers and policymakers with finding new ways to tackle maternity disparities.

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