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Our Pregnancy Physiology Pattern Prediction (4P) multi-centre study, supported by the Oxford NIHR Biomedical Research Centre involved 1043 women who contributed their vital signs to allow us to develop modern day normal ranges for women during pregnancy and after birth. Working with the Oxford Institute of Biomedical Engineering we developed an innovative system, allowing women to measure their own vital signs at home. We used these measurements to develop new reference ranges which change through pregnancy and the two weeks after, changing what is taught (hear journal podcast from March 2020). Our ranges underpin the new National Maternal Early Warning Score (hear Professor Watkinson discussing the new score here and read the practice guidance (BMJ 2020;370:m2248).

This work led to an ongoing programme grant funding from the National Institute for Health and Care Research (Defining, Recognising and Escalating Maternal Early Deterioration (DREaMED): Decreasing inequality through improved outcomes, NIHR204430 ). This six year multi-centre collaboration (commencing May 2023), including working with NHS England/Improvement, will define new “near miss” and “severe morbidity” criteria for use in the NHS and beyond, define existing maternal early warning score performance, develop an new electronic maternal early warning score incorporating  all relevant risk factors (including for example laboratory variables as well as vital signs) using traditional statistical and artificial intelligence techniques, design and implement an electronic maternal early warning score interface and test the outcomes. The programme of work is particularly focused on decreasing health inequalities in this population. The programme is joined by both clinicians and statisticians working on National Institute for Health and Care Research-funded doctoral projects.


Postpartum-Specific Vital Sign Reference Ranges. Published February 2021. 

Gestation-Specific Vital Sign Reference Ranges in Pregnancy. Published March 2020 

Trends of blood pressure and heart rate in normal pregnancies: a systematic review and meta-analysis Published September 2019 

Pregnancy physiology pattern prediction study (4P study): protocol of an observational cohort study collecting vital sign information to inform the development of an accurate centile-based obstetric early warning score. Published September 2017