Self-management of blood pressure following a hypertensive pregnancy
| ISRCTN | ISRCTN11042045 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN11042045 |
| IRAS number | 332333 |
| Secondary identifying numbers | CPMS 59560, IRAS 332333 |
- Submission date
- 17/05/2024
- Registration date
- 11/06/2024
- Last edited
- 22/10/2025
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Circulatory System
Plain English summary of protocol
Background and study aims
High blood pressure (BP) (hypertension) during and following pregnancy affects around 80,000 women each year in the UK, and can lead to very serious problems such as pre-eclampsia or stroke. In the longer term, women who had high BP during pregnancy have an increased risk of heart attack and stroke, and this seems to be linked to their blood pressure in the early weeks following birth.
After birth, women’s BP can remain elevated, but in most cases it returns to normal over 2–12 weeks. During this time, blood pressure medication needs to be adjusted to achieve the correct control. Previous research suggests that better BP control during this time is associated with improved long-term health outcomes. This trial aims to test whether women with high BP, can achieve lower blood pressure than is usual in the weeks and months following birth, through self-monitoring and adjusting their own medication.
Who can participate?
Women aged 18 years or over in the postnatal period who have had a hypertensive pregnancy
What does the study involve?
Women recruited to the study will be randomly assigned to one of two groups: either monitoring their own blood pressure and using this to manage their blood pressure medication, or receiving the standard care that they would otherwise have. Participants allocated to ‘usual care’ will have their BP monitored and medication adjusted by their obstetrician, GP and midwife as normal. Participants allocated to the ‘self-management’ group will use a home BP monitor daily following discharge from hospital after birth until their blood pressure has settled, and then once a week. They will be provided with an individualised schedule (via a specially designed app) for gradually adjusting their medication(s) in line with their BP readings, overseen by their obstetrician, GP and midwife.
What are the possible benefits and risks of participating?
Taking part in the study may give participants better information and understanding about their blood pressure. If possible, it is hoped that achieving better blood pressure control in the period after birth may contribute to better long-term health outcomes. However, the study is being conducted as it is not clear if medication adjustments (facilitated by the app and directed by clinicians’ review) can achieve better blood pressure control than standard care.
It is hoped that information from this work will improve the care of women with raised blood pressure after birth in the future. The researchers think there is very little risk of harm in taking part.
All women will still receive their usual care while in this study. The only disadvantage is the extra time taken to measure blood pressure for women allocated to the self-management group and the additional time spent with the study team at the follow-up visits. Other than the time taken to undertake the study, we do not anticipate any other disadvantage from taking part.
Where is the study run from?
University of Oxford - Primary Care Clinical Trials Unit (UK)
When is the study starting and how long is it expected to run for?
July 2023 to January 2027
Who is funding the study?
NIHR - Programme Grants for Applied Research (UK)
Who is the main contact?
SNAP2 Trial Manager, snap2trial@phc.ox.ac.uk
Contact information
Public, Scientific, Principal investigator
Nuffield Dept Primary Care Health Sciences
RPC Building
Woodstock Road
Oxford
OX2 6GG
United Kingdom
 ORCID ID |
0000-0003-3638-028X |
|---|---|
| Phone | +44 (0)1865 617852 |
| snap2trial@phc.ox.ac.uk |
Study information
| Study design | Multicentre interventional randomized controlled trial |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Home, Hospital |
| Study type | Efficacy |
| Participant information sheet | Not available in web format, please use contact details to request a participant information sheet |
| Scientific title | Randomised controlled trial of self-management of postnatal antihypertensive treatment |
| Study acronym | SNAP2 |
| Study objectives | Self-management of blood pressure reduces diastolic blood pressure following a hypertensive pregnancy |
| Ethics approval(s) |
Approved 09/05/2024, South Central - Oxford B Research Ethics Committee (Bristol Research Ethics Committee Centre, Whitefriars Level 3, Block B Lewin's Mead, Bristol, BS1 2NT, United Kingdom; +44 (0)207 104 8178; oxfordb.rec@hra.nhs.uk), ref: 24/SC/0071 |
| Health condition(s) or problem(s) studied | Monitoring of hypertension in women following hypertensive pregnancy |
| Intervention | Women recruited to the study will be randomly assigned to one of two groups: either monitoring their own blood pressure and using this to manage their blood pressure medication, or receiving the standard care that they would otherwise have. Participants allocated to the ‘self-management’ group will use a validated monitor and titration of antihypertensive therapy guided by a specially developed digital intervention (a smartphone app), daily following discharge from hospital after birth until their blood pressure has settled, and then once a week. They will be provided with an individualised schedule via the app for gradually adjusting their medication(s) in line with their BP readings. This will be overseen, with any change approved by their own health care professionals who review the uploaded readings and respond to tele-monitored abnormal readings in a timely fashion. All intervention participants will in addition receive usual NHS care. Participants allocated to ‘usual care’ will have their BP monitored and medication adjusted by their obstetrician, GP and midwife as normal. Randomisation will be completed by site staff on randomising software Sortition. |
| Intervention type | Other |
| Primary outcome measure | Current primary outcome measures as of 22/10/2025: Mean daytime ambulatory diastolic blood pressure measured using an ambulatory blood pressure monitor at 26-39 weeks. _____ Previous primary outcome measures: Mean daytime ambulatory diastolic blood pressure measured using an ambulatory blood pressure monitor at 26 weeks. |
| Secondary outcome measures | Current secondary outcome measures as of 22/10/2025: 1. Mean daytime ambulatory systolic blood pressure measured using an ambulatory blood pressure monitor at 26-39 weeks 2. Mean 24-hour and nocturnal ambulatory blood pressure measured using an ambulatory blood pressure monitor at 26-39 weeks 3. Systolic and diastolic blood pressure at follow-up (mean of 2nd/3rd readings and mean of 2nd – 6th readings) measured in clinic or at home at baseline, 6 weeks, 12 weeks, 26-39 weeks and 48-60 weeks 4. Maternal health-related quality of life measured using EQ-5D-5L health questionnaire results at baseline, 6 weeks, 12 weeks, 26-39 weeks and 48-60 weeks 5. Anxiety associated with self-management of BP measured using the short-form anxiety inventory questionnaire at baseline, 12 weeks and 48-60 weeks 6. Medication adherence measured by the presence of urinary antihypertensive metabolites at 6 weeks and the Medication Adherence Rating Scale (MARS) at baseline and 6 weeks 7. Postnatal readmissions measured using all-cause admissions, pregnancy hypertension admissions and cardiovascular events at records review 8. Healthcare resource use and cost analysis of key cost drivers between study arms measured using participant resource use data collection at baseline, 12 weeks, 26-39 weeks and 48-60 weeks 9. Cost-consequence analysis presenting costs and key outcomes in a disaggregated manner measured over the trial period 10. Long-term modelled cost-utility analysis using quality-adjusted life years (QALYs) measured using Modelled lifetime horizon and Sensitivity analysis to judge time to benefit/harm 11. Qualitative process evaluation measured using in-depth semi-structured interviews over the trial period _____ Previous secondary outcome measures: 1. Mean daytime ambulatory systolic blood pressure measured using an ambulatory blood pressure monitor at 26 weeks 2. Mean 24-hour and nocturnal ambulatory blood pressure measured using an ambulatory blood pressure monitor at 26 weeks 3. Systolic and diastolic blood pressure at follow-up (mean of 2nd/3rd readings and mean of 2nd – 6th readings) measured in clinic or at home at baseline, 6 weeks, 12 weeks, 26 weeks and 52 weeks 4. Maternal health-related quality of life measured using EQ-5D-5L health questionnaire results at baseline, 6 weeks, 12 weeks, 26 weeks and 52 weeks 5. Anxiety associated with self-management of BP measured using the short-form anxiety inventory questionnaire at baseline, 12 weeks and 52 weeks 6. Medication adherence measured by the presence of urinary antihypertensive metabolites at 6 weeks and the Medication Adherence Rating Scale (MARS) at baseline and 6 weeks 7. Postnatal readmissions measured using all-cause admissions, pregnancy hypertension admissions and cardiovascular events at records review 8. Healthcare resource use and cost analysis of key cost drivers between study arms measured using participant resource use data collection at baseline, 12 weeks, 26 weeks and 52 weeks 9. Cost-consequence analysis presenting costs and key outcomes in a disaggregated manner measured over the trial period 10. Long-term modelled cost-utility analysis using quality-adjusted life years (QALYs) measured using Modelled lifetime horizon and Sensitivity analysis to judge time to benefit/harm 11. Qualitative process evaluation measured using in-depth semi-structured interviews over the trial period |
| Overall study start date | 01/07/2023 |
| Completion date | 31/01/2027 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 50 Years |
| Sex | Female |
| Target number of participants | 690 |
| Key inclusion criteria | 1. Participant is willing and able to give informed consent for participation in the study 2. People who have recently given birth within the last 7 days 3. Aged 18 years or above 4. Participant with pregnancy hypertension including: chronic/essential hypertension (predating current pregnancy or requiring treatment before 20/40), or gestational hypertension (new-onset hypertension from 20/40 of index pregnancy) or pre-eclampsia (hypertension (GH or with proteinuria or metabolic changes), prior to their discharge from hospital post-delivery. 5. Participant still requiring antihypertensive medication at randomisation following delivery 6. Able and willing to comply with trial requirements 7. Willing to allow their primary and secondary healthcare teams, if appropriate, to be notified of participation in the trial 8. Access to a smartphone compatible with the app |
| Key exclusion criteria | 1. Participant does not wish to self-monitor/self-manage their blood pressure 2. Participant already taking part in another trial that might affect their anti-hypertensive prescription |
| Date of first enrolment | 24/06/2024 |
| Date of final enrolment | 30/11/2025 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centres
Headley Way
Headington
Oxford
OX3 9DU
United Kingdom
Oxford Road
Manchester
M13 9WL
United Kingdom
Guy's Hospital
Great Maze Pond
London
SE1 9RT
United Kingdom
369 Fulham Road
London
SW10 9NH
United Kingdom
80 Newark Street
London
E1 2ES
United Kingdom
Skipton Road
Steeton
Keighley
BD20 6TD
United Kingdom
Whinney Heys Road
Blackpool
FY3 8NR
United Kingdom
Calow
Chesterfield
S44 5BL
United Kingdom
Poole Hospital
Longfleet Road
Poole
BH15 2JB
United Kingdom
Haslingden Road
Blackburn
BB2 3HH
United Kingdom
Turner Road
Colchester
CO4 5JL
United Kingdom
St Marys Hospital
South Wharf Road
London
W2 1BL
United Kingdom
Kingston upon Thames
KT2 7QB
United Kingdom
Lewisham High Street
London
SE13 6LH
United Kingdom
Westcliff-on-sea
SS0 0RY
United Kingdom
London Road
Reading
RG1 5AN
United Kingdom
Lyndhurst Road
Worthing
BN11 2DH
United Kingdom
Watford General Hospital
Vicarage Road
Watford
WD18 0HB
United Kingdom
Frimley
Camberley
GU16 7UJ
United Kingdom
Magdala Avenue
London
N19 5NF
United Kingdom
Whielden Street
Amersham
HP7 0JD
United Kingdom
Sponsor information
University/education
Research Governance, Ethics and Assurance
Boundary Brook House
Churchill Drive
Headington
Oxford
OX3 7GB
England
United Kingdom
| Phone | +44 (0)1865616497 |
|---|---|
| RGEA.Sponsor@admin.ox.ac.uk | |
| Website | https://researchsupport.admin.ox.ac.uk/contacts/rgea#collapse3089471 |
"ROR" |
https://ror.org/052gg0110 |
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- NIHR Programme Grants for Applied Research, PGfAR
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 30/06/2027 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | 1. Planned publication in a high-impact peer-reviewed journal and scientific conferences 2. Dissemination via dedicated events and social media platforms 3. Dissemination to participating sites |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are/will be available upon request from the chief investigator Prof. Richard McManus (richard.mcmanus@phc.ox.ac.uk) |
Editorial Notes
22/10/2025: The following changes were made to the trial record:
1. The completion date was changed from 01/12/2026 to 31/01/2027.
2. The primary outcome measures were changed.
3. The secondary outcome measures were changed.
4. The study website was changed from https://www.phctrials.ox.ac.uk/studies/snap2 to https://www.phctrials.ox.ac.uk/recruiting-trials/snap-2.
5. The target number of participants was changed from 628 to 690.
6. The date of final enrolment was changed from 01/10/2025 to 30/11/2025.
7. The study participating centres were updated.
8. The plain English summary was updated to reflect these changes.
17/05/2024: Study's existence confirmed by the South Central - Oxford B Research Ethics Committee.
