Date published: 31 May, 2023
Date last updated: 2 June, 2025
Children and young people, Integrated care, Maternity, Nursing, midwifery and care

Recommendations for digital blood pressure monitoring in maternity services (portable devices)

Updated June 2025, version 2

Introduction

This publication provides evidence to support using correctly calibrated and validated digital blood pressure monitors for pregnancy in maternity services.

This priority strengthens our NHS Long Term Plan and CORE 20Plus 5 commitments to transform maternity services across integrated care boards (ICBs), and reduce unequal health outcomes for women and babies.

Appropriate digital blood pressure monitoring devices in maternity services and across associated services in the patient pathway can help reduce morbidity and mortality.

Correct use of validated digital blood pressure monitors within usual care pathways will help save the lives of women and babies by identifying conditions earlier and more accurately, facilitating appropriate treatment.

This will enable the reduction in the burden of disease while lowering anxiety for women and families.

The audience for this document includes maternity services and fetal medicine, directors and heads of midwifery, directors of nursing, and clinical directors of maternity (or obstetrics) across England.

The recommendations listed here are primarily directed towards devices that are portable blood pressure monitors and for non-complex devices that do not also monitor a range of other measurements besides blood pressure.

These recommendations do not cover devices that provide a range of physiological measurements simultaneously within secondary care settings, such as vital signs equipment currently used in maternity units.

Recommendations

Based on a review of the evidence for benefits and performance, the Office of the Chief Scientific Officer for NHS England, alongside experts consulted from across the system, makes 5 recommendations for optimising the use of validated and calibrated digital blood pressure monitors in maternity services.

These recommendations cover use of portable digital blood pressure monitors, both at home and in clinical environments, including hospital and general practice settings.

  1. Digital portable blood pressure monitoring devices, that are validated for pregnancy and pre-eclampsia, can be used as the diagnostic screening tool in maternity services.
  2. A woman’s blood pressure should be measured at every antenatal appointment, including the booking appointment, using suitable digital blood pressure devices validated for pregnancy and pre-eclampsia.
  3. Digital devices must be approved and validated for use in pregnant women. The British and Irish Hypertension Society and STRIDE BP both maintain a list of devices that have been independently reviewed and approved for use during pregnancy, either at home or in office/clinical settings. Differences exist between the 2 lists. Clinicians should decide which validated monitors best meet clinical needs in consultation with their local clinical engineering unit
  4. Maternity services should implement a programme to replace aneroid devices over time with digital devices validated for pregnancy and pre-eclampsia and the maintenance regimen for digital devices should check their accuracy against the gold standard.
  5. NHS and social care organisations, can use the Automated Blood Pressure Monitor Dynamic Purchasing System (DPS) to procure blood pressure machines at competitive prices. The DPS also makes procurement quicker and easier for NHS and other organisations.

Background

The long-term health outcomes for women and babies exposed to hypertensive disorders could be reduced by avoiding delays in the diagnosis and management of hypertension.

The Ockenden report refers to hypertension, blood pressure and eclampsia 172 times: in many of the cases it reviewed it considered that outcomes for women and babies could have been improved with higher quality diagnosis and hypertensive care in the maternity pathway.

The Office of the Chief Scientific Officer for NHS England has reviewed the evidence for the benefits and performance of digital versus aneroid blood pressure monitors, and recommends that digital monitors already validated for use in pregnancy, should replace aneroid devices as a primary screening tool.

An accurate baseline for a woman’s blood pressure should be established in the first trimester, with subsequent blood pressure readings taken regularly.

The scale and impact of hypertension in pregnancy is outlined in the NICE clinical knowledge summary of hypertension in pregnancy and listed below:

  • Hypertensive disorders occur in 8 to 10% of all pregnancies.
  • Chronic hypertension has been reported to complicate 0.6 to 2.7% of pregnancies.
  • Gestational hypertension is probably under-reported, with recorded rates of 4.2 to 7.9%.
  • Pre-eclampsia rates range from 1.5 to 7.7% but depend on parity: 4.1% of women in their first pregnancy and 1.7% of women in their second pregnancy have pre-eclampsia.
  • Haemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome or elevated liver enzymes low platelet syndrome (ELLP syndrome).
    • Incidence estimates vary from 0.5–7.6 per 1000 deliveries, and between 8–24% of cases with severe pre-eclampsia/eclampsia. 
  • Eclampsia is a rare but serious condition. Between April 2023 and March 2024 eclampsia complicated 270 deliveries in England, equivalent to 5 per 10,000 births (NHS maternity statistics, England, 2023-24).

Type of blood pressure monitors (sphygmomanometers)

Broadly, there are 2 types of blood pressure monitors: aneroid and digital.

Mercury devices have been phased out for health and environmental reasons.

Digital devices (when calibrated and validated for the intended use) have advantages over aneroid monitors.

Digital devices are less susceptible to performance errors and require less frequent replacement, calibration and maintenance checks in comparison with aneroid devices, and are also more suitable for self-monitoring at home because their use requires minimal training.

Pregnancy and blood pressure

The accuracy of digital blood pressure devices that are validated and calibrated for the general population is not necessarily assured for pregnant women.

The physiological changes in pregnancy (increased heart rate, stroke volume and reduced total peripheral resistance) are accounted for in digital devices that are validated and calibrated specifically for use in pregnancy.

Aneroid monitors do require calibration, but do not require validation as auscultation is the gold standard which digital devices are validated against.

The British and Irish Hypertension Society and STRIDE BP both publish lists of independently reviewed and approved devices for home and office/hospital blood pressure monitoring during pregnancy.

There are differences between the 2 lists because of the variation in the protocols the organisations use to assess devices.

Clinicians should review these lists and decide which ones meet their clinical needs in consultation with their local clinical engineering unit.

Please also note the Medicines and Healthcare products Regulatory Agency (MHRA) recommendations on blood pressure measurement devices, which build on the 2 organisations’ lists above.

The MHRA recommendations specify that digital blood pressure devices need to be suitably validated and calibrated for pregnancy and pre-eclampsia before they are suitable for use in maternity settings.

Maintaining accuracy of readings

Inaccurate readings are strongly associated with the poor maintenance of blood pressure monitors (regardless of the device type).

All devices and cuffs should be examined for visual signs of damage and calibrated at the frequency the manufacturer specifies.

As noted above, digital devices are less susceptible to performance errors and require less frequent replacement, calibration, and maintenance checks in comparison with aneroid devices.

Cuff size

Accurate blood pressure measurement, regardless of device type, requires the use of a cuff that is of the appropriate size for person’s limb. A tape measure should be used to assess the person’s arm circumference if appropriate.

Cuff size is an important consideration when validating monitors. Those procuring monitors for use in pregnancy should ensure the range of cuff sizes for which a device has been validated is available.

Where blood pressure is monitored over a short time (hours), the same sized cuff should be used for each measurement to ensure accuracy. Re-measurement of arm circumference over the course of pregnancy may be warranted to allow for alteration in cuff size.

Cuffless devices are a recent addition to the blood pressure monitoring device market, but their accuracy is not well established, and they are not recommended for clinical use.

Device classification and regulation

The MHRA requires that for a medical device to be marketed in the UK it must be UKCA, CE or UKNI marked as a medical device, conformity assessed and registered with the MHRA.*

[*Medicines and Healthcare products Regulatory Agency (2020; last update March 2025). Register medical devices to place on the market.]

A number of blood pressure monitors are described by the MHRA in Blood pressure measurement devices, a guidance document on the purchase, management and use of blood pressure measurement devices.

Health inequalities considerations

Using suitable digital blood pressure monitors will help improve equity of services for all, including pregnant women from black and other ethnic minority backgrounds, who are particularly at an increased risk of high blood pressure.

It is therefore important to use blood pressure monitors that have been validated for use in pregnancy.

Home monitoring in pregnancy and post-natal period

Pregnant women with chronic or gestational hypertension are at greater risk compared to normotensive women of developing pre-eclampsia and its associated complications.

There is no evidence from large, adequately powered trials in higher risk normotensive women and women with hypertension that self-monitoring of blood pressure in pregnancy (for example, at home) changes clinical outcomes.

However, these trials demonstrated no safety concerns for self-monitoring and many pregnant women reported that self-monitoring gave them additional reassurance.

Pregnant women with hypertension who are otherwise well and postnatal women can be signposted to accurate and acceptable means of monitoring hypertension at home using digital devices to complement existing maternity pathways.

Large surveys of pregnant women show that around half of women with hypertension and around one-fifth who are normotensive do self-monitor their blood pressure but do not necessarily share the readings with healthcare professionals.*

There is no evidence as to whether measurements from self-monitoring can be safely used to adjust the number of outpatient appointments and inpatient days a pregnant woman needs.

However, they may be helpful for the management of women who find it difficult to regularly attend appointments in person, such as those with disabilities or who live in rural communities. 

Digital blood pressure monitors should be accompanied by a factsheet describing:

  • the signs and symptoms of conditions associated with changes in blood pressure, including pre-eclampsia, that women should be aware of as potentially concerning – for example, headaches, problems with vision such as blurring or flashing before the eyes, swelling in the face, hands or feet, and abdominal pain
  • the blood pressure range outside of which readings are a potential concern

Women should consult their maternity service (for example, the hospital or community midwife) or their GP at the earliest opportunity should they have concerning signs, symptoms or blood pressure readings.

Further resources

Contributors

  • Dr Eleri Adams, GIRFT Lead, Neonatology, NHS England
  • Dr Lisa Anderson, Heart Failure Consultant, St George’s University Hospitals NHS Foundation Trust
  • Robert Annan, Programme Lead, NHS England
  • Lucy Bonsall, Senior Project Manager, CVD Prevention Clinical Policy Unit, NHS England
  • Dr Victoria Chalker, Deputy Chief Scientific Officer, NHS England
  • Professor Lucy Chappell, Chief Scientific Adviser, Department of Health and Social Care; Chief Executive Officer, National Institute of Health Research
  • Sarah Cooper, Cardiac Clinical Scientist, South-West Scientific Regional Lead
  • Professor Anna David, Consultant in Obstetrics & Maternal Fetal Medicine, University College London
  • Dr Ngozi Edi-Osagie, National Clinical Director for Neonatology, NHS England
  • Professor Dame Sue Hill, Chief Scientific Officer, NHS England
  • Heart Failure Expert Advisory Group, NHS England
  • Hypertension Oversight Group, CVD Prevention Clinical Policy Unit, NHS England
  • Professor Edward Johnstone, Consultant Obstetrician, Manchester University NHS Foundation Trust
  • Professor Jenny Myers, Consultant Obstetrician, Manchester University NHS Foundation Trust
  • Professor Richard McManus, Nuffield Department of Primary Care Health Sciences, University of Oxford
  • National Clinical Engineering Network, NHS England
  • Professor Donald Peebles, National Clinical Director for Maternity Programme, NHS England
  • Charlie Podschies, Policy Lead for Clinical Pathways, Maternity and Neonatal Programme, NHS England
  • Sue Robinson, Senior Delivery Manager NHS @ Home, NHS England
  • Professor Andy Shennan, Consultant Obstetrician, King’s College London
  • Stephanie Taylor, Medicines and Healthcare products Regulatory Agency
  • Karen Thirsk, Midwife and Senior Project Manager Pathway Improvement Team Maternity and Neonatal Programme, NHS England
  • Professor Paul White, Consultant Clinical Scientist and Head of Clinical Engineering, Cambridge University Hospitals NHS Foundation Trust; East of England Clinical Engineering Lead, Medical Technology Research Centre, Anglia Ruskin University

Publication reference: PRN01794 (version 2)

Date published: 31 May, 2023
Date last updated: 2 June, 2025