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Original article
Development and evaluation of a novel Vital Signs Alert device for use in pregnancy in low-resource settings
  1. Hannah L Nathan1,
  2. Nicola Vousden1,
  3. Elodie Lawley1,
  4. Annemarie de Greeff2,
  5. Natasha L Hezelgrave1,
  6. Nicola Sloan1,
  7. Nina Tanna1,
  8. Shivaprasad S Goudar3,
  9. Muchabayiwa F Gidiri4,
  10. Jane Sandall1,
  11. Lucy C Chappell1,
  12. Andrew H Shennan1
  1. 1 Department of Women and Children’s Health, King’s College London, London, UK
  2. 2 Validate Global, Kimberley, South Africa
  3. 3 JNMC Women’s and Children’s Health Research Unit, KLE University, Belagavi, India
  4. 4 College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
  1. Correspondence to Dr Hannah L Nathan, Department of Women and Children’s Health, King’s College London, London SE1 7EH, UK; hannah.nathan{at}


Objectives Haemorrhage, hypertension, sepsis and abortion complications (often from haemorrhage or sepsis) contribute to 60% of all maternal deaths. Each is associated with vital signs (blood pressure (BP) and pulse) abnormalities, and the majority of deaths are preventable through simple and timely intervention. This paper presents the development and evaluation of the CRADLE Vital Signs Alert (VSA), an accurate, low-cost and easy-to-use device measuring BP and pulse with an integrated traffic light early warning system. The VSA was designed to be used by all cadres of healthcare providers for pregnant women in low-resource settings with the aim to prevent avoidable maternal mortality and morbidity.

Methods The development and the mixed-methods clinical evaluation of the VSA are described.

Results Preliminary fieldwork identified that introduction of BP devices to rural clinics improved antenatal surveillance of BP in pregnant women. The aesthetics of the integrated traffic light system were developed through iterative qualitative evaluation. The traffic lights trigger according to evidence-based vital sign thresholds in hypertension and haemodynamic compromise from haemorrhage and sepsis. The VSA can be reliably used as an auscultatory device, as well as its primary semiautomated function, and is suitable as a self-monitor used by pregnant women.

Conclusion The VSA is an accurate device incorporating an evidence-based traffic light early warning system. It is designed to ensure suitability for healthcare providers with limited training and may improve care for women in pregnancy, childbirth and in the postnatal period.

  • affordable
  • diagnostics
  • global Health
  • obstetrics
  • hypertension

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  • Contributors Design: HLN, NV, SG, MFG, NLH, AHS. Planning: HLN, NV, AdG, NLH, NS, NT, SG, MFG, LCC, AHS. Conduct: HLN, EL, NS, NT, AdG, JS. Data analysis: HLN, EL, NS, NT, JS, LCC, AHS. Manuscript writing: HLN, NV, LCC, AHS. Responsible for the overall content: AHS.

  • Funding Funded by Bill & Melinda Gates Foundation (Grant ID: OPP1086183).

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval Stellenbosch University Ethics Committee (N14/06068), University of Cape Town Ethics Committees (410/2014) and the University of the Free State Ethics Committee (230408-011).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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