Project objectives

1. What are the thresholds for the diagnosis of raised blood pressure in pregnancy using self-monitored blood pressure? (SR, modelling, pilot work)
2. What is the optimal frequency, duration and timing of self-monitoring of BP in pregnancy? (SR, pilot work, modelling)
3. What is the optimum protocol for self-monitoring of blood pressure in pregnancy and can this protocol fit into the diagnostic pathway for pre-eclampsia? (SR, pilot work, modelling and qualitative study)
4. How acceptable is the proposed self-monitoring intervention to both pregnant women and their health professionals and what are the barriers to its implementation? (SR and qualitative study)
5. What would be a reasonable expectation of the recruitment rate to a future trial of self-monitoring of blood pressure in pregnancy? (pilot work)

Changes to project objectives

Project length

Recruitment was slower than we hoped and continued until the end of 2013. Participants were followed in the study until September 2014, the study was originally due to finish in February 2014. This was extended the end date to 31/03/2015 to allow chasing of clinical data from notes.

Brief summary

Background

Raised blood pressure affects approximately 10% of pregnancies worldwide, of which around half develop pre-eclampsia. Early detection and treatment of raised blood pressure is therefore paramount. Self-monitoring of blood pressure is widely practiced by adults with hypertension but few data exist in pregnancy.

Objective

This program of work aimed to provide preliminary evidence that self-monitoring of blood pressure could improve the detection of gestational hypertensive disorders.

This study contained four work streams: 1) Systematic Review 2) Pilot study 3) Qualitative study 4) Statistical modelling

1) Systematic review

Aim

To assess the current evidence for the use of self-monitoring of BP in pregnancy.

Methods

Medline and nine other electronic databases were searched to capture all the relevant literature concerning schedules for self-monitoring of blood pressure in pregnancy and self-monitored BP thresholds for the diagnosis of pre-eclampsia and gestational hypertension. At the full text stage all investigators that carried out home and clinic BP monitoring were contacted to request individual patient data. Where possible, data on all patients was included.

Results

A total of 9 eligible studies were identified from which home and office BP data was available for 1085 participants. The average difference in BP was 0.51/1.29mmHg. There was significant heterogeneity between studies, which could be accounted for by the use of un-validated monitors, monitoring at different gestation and different monitoring schedules. Individual patient data analysis using data from 5 studies (n=414) showed a clinic-home systolic difference of 0.6mmHg and diastolic difference of 0.53mmHg at 5-14 weeks and similar minimal differences throughout pregnancy. The results showed that white coat hypertension (16.10%) was more prevalent than masked hypertension (5.57%) and that white coat hypertension was equally prevalent as true hypertension (16.41%).

Conclusion

We have found that self-monitoring is feasible, popular with patients, and potentially useful in the diagnosis and management of gestational hypertension. The available literature suggests a diagnostic threshold equivalent to clinic threshold would be suitable for home monitoring during pregnancy.

2) Pilot study

Aim

To provide preliminary evidence that self-monitoring of blood pressure could improve the detection of gestational hypertensive disorders.

Methods

Prospective un-blinded observational pilot study of blood pressure self-monitoring in women at higher risk according to NICE guidance. Following recruitment at 12 -16 weeks gestation, participants monitored their own blood pressure using a validated device three times per week in addition to usual antenatal care with an optional text based telemonitoring service.

Results

201 participants were recruited from April 2013 to January 2014. At baseline, women had a mean age of 31, a mean blood pressure of 116/70 mmHg and mean BMI 28.2. Thirty (15%) of participants did not complete self-monitoring throughout pregnancy. Comparison of home vs clinic BP measurement showed good agreement throughout pregnancy.

Conclusion

Self-monitoring of blood pressure in pregnancy is feasible and acceptable to women. Self-monitored blood pressure was similar to that measured in the clinic setting and data so far suggests it could be used to improve the detection of raised BP during pregnancy.

3) Qualitative study

Objective

To understand women’s experiences of taking part in an observational pilot study of self-monitoring of blood pressure during pregnancy (BuMP).

Sample

Women who had taken part in the BuMP pilot study were invited to take part in an interview. Out of 201 women taking part, 15 women agreed to talk about their experiences of self-monitoring their blood pressure during pregnancy.

Methods

Narrative interviews were conducted by a qualitative researcher and transcribed for analysis. A framework approach was used for analysis of the interview data.

Results

Women in the pilot study who agreed to be interviewed reported general willingness to engage with monitoring their own BP, feeling that it could reduce anxiety around their health during pregnancy, particularly if they had previous experience of raised blood pressure or pre-eclampsia. They felt able to incorporate self-monitoring into their weekly routines, although this was harder post-partum. Self-monitoring of blood pressure made them more aware of the risks of hypertension and pre-eclampsia in pregnancy. Feelings of reassurance and empowerment were commonly reported.

Conclusions

Self-monitoring in pregnancy was both acceptable and feasible to women in this small pilot study, suggesting a full trial will be possible.

Results will be incorporated into a forthcoming “healthtalkonline” module.

4) Statistical modelling

Using our pilot data we have been able to estimate the test performance of home blood pressure monitoring in pregnancy. We are currently designing an optimised monitoring protocol for a large substantive trial. It appears that self-monitoring may be able to detect raised blood pressure around a fortnight before current measures and we have developed and submitted a programme grant application to test this hypothesis.

Overall we have achieved our aims at the start of the study and currently have three papers close to submission (systematic review, BUMP pilot study and BUMP patient experience). We have published a clinical review paper in the BMJ and a diagnostic report via the DEC in Oxford.

Plain English summary

Raised blood pressure is common in pregnancy, affecting about one in ten women. For many of these women the raised blood pressure, if combined with protein leaking into the urine, is an indication of pre-eclampsia. This can lead to eclampsia - a serious condition with seizures and a high mortality rate. Around one in six women who die in pregnancy have pre-eclampsia or eclampsia.

Diagnosing pre-eclampsia requires monitoring of blood pressure and urine, typically by midwives, at intermittent times during pregnancy coinciding with antenatal visits. Women considered to be at higher risk for pre-eclampsia, for instance due to age or a previous history, require more frequent monitoring. Self-monitoring of blood pressure could provide additional readings with little or no disturbance of lifestyle.

We have carried out initial work to investigate whether blood pressure measurement by pregnant women themselves might improve detection of raised blood pressure and pre-eclampsia whilst empowering pregnant women. This has included a review of the literature, a feasibility study, interviews with study participants and some mathematical modelling.

Our results suggest that self-monitoring of blood pressure in pregnancy is feasible and acceptable to women and could be used to improve the detection of raised BP during pregnancy. We have used these results to bid for a programme grant to undertake further work around self-monitoring in pregnancy including a large trial of the BUMP intervention. We are preparing a series of papers for publication.

Dissemination

Published articles

1. Hodgkinson JA, Tucker KL, Crawford C, Greenfield SM, Heneghan C, Hinton L, Khan K, Locock L, Mackillop L, McCourt C, Selwood M, McManus RJ. Is self monitoring of blood pressure in pregnancy safe and effective? BMJ. 2014;349:g6616. doi: 10.1136/bmj.g6616.
   http://www.bmj.com/content/349/bmj.g6616.long
2. K. Tucker, E. Brunt M. Thompson, R. McManus, C. Crawford, C. Heneghan, N. Robberts and A. Plüddemann (March 2014). Urinalysis self-testing in pregnancy. Horizon scanning report 2014.
   http://www.oxford.dec.nihr.ac.uk/reports-and-resources/horizon-scanning-reports/urinalysis-self-testing-in-pregnancy

Planned articles

1. K.L. Tucker, J. Hodgkinson, C. Bankhead, N. Roberts, R Stevens, É. Rey, C. Lo, M. Chandiramani, R. Taylor, R. North, J. Waugh, M. Brown and R. J. McManus. (2015) Under pressure: Can self-monitoring of blood pressure in pregnancy improve detection of gestational hypertension? An individual patient data meta-analysis.
2. Katherine L. Tucker, Carole Crawford, James A. Hodgkinson, Clare Bankhead, Kathryn Taylor, Sheila M. Greenfield, Carl Heneghan, Lisa Hinton, Khalid S. Khan, Louise Locock, Lucy Mackillop, Christine McCourt, Mary Selwood, Richard Stevens, and Richard J. McManus.   Self-monitoring of blood pressure in pregnancy: The BuMP study (2015).
3. Lisa Hinton, Louise Locock, Katherine L. Tucker, Sheila M. Greenfield, Carole Crawford, James A. Hodgkinson, Clare Bankhead, Christine McCourt, Kathryn Taylor, Carl Heneghan, Khalid S. Khan, Lucy Mackillop, Mary Selwood, Richard Stevens, and Richard J. McManus. Blood pressure monitoring in pregnancy: patient and staff perspectives; A qualitative study (2015).

Conference presentations

1. K.L.Tucker, C. Bankhead, J. Hodgkinson, S. Greenfield, C. Crawford, C. Heneghan, N. Roberts, and R.J. McManus. Under pressure: Can self-monitoring of blood pressure in pregnancy be used to detect and manage gestational hypertension? An individual patient meta-analysis(SAPC SW 2015 Oral).
2. L. Mackillop, K. Tucker, L. Loerup R. Kaplan, J. Newstead-Angel (2014) Web-enabled pregnancy: using digital health solutions for the detection and management of medical conditions in pregnancy (ISOM Oral presentation).
3. C. Crawford, K.L. Tucker, J.A. Hodgkinson, L. Hinton, R. Stevens, K.S. Taylor, M. Selwood, K. Khan, L. Locock, C. Bankhead, C. McCourt, C. Heneghan, S.M. Greenfield, A. Pirie, L. Mackillop, and R.J. McManus (2014) Self-monitoring of blood pressure in pregnancy: The BuMP study (SAPC 2014 Oral).
4. K.L. Tucker, C. Crawford, J.A. Hodgkinson, L. Hinton, R. Stevens, K.S. Taylor, M. Selwood, K. Khan, L. Locock, C. Bankhead, C. McCourt, C. Heneghan, S.M. Greenfield, A. Pirie, L. Mackillop, and R.J. McManus (2014) Self-monitoring of blood pressure in pregnancy: The BuMP study (UK Pregnancy Summit 2014 Oral).
5. L.Hinton, K.L.Tucker, S.Greenfield, R.McManus and L.Locock Blood pressure monitoring in pregnancy: patient and staff perspectives. A qualitative study (SAPC 2014 oral).
6. L.Hinton, K.L.Tucker, S.Greenfield, R.McManus and L.Locock Blood pressure monitoring in pregnancy: patient and staff perspectives. A qualitative study (EACH 2014).
7. K.L.Tucker, C. Crawford, J. Hodgkinson , C. Bankhead, S. Greenfield, C. Heneghan, K. Khan, L. Locock, L.Hinton, C. McCourt, M. Selwood, N. Roberts, R. Stevens and R.J. McManus (2014) Self-monitoring of blood pressure in pregnancy: The BuMP study (SW SAPC poster).
8. K.L.Tucker J. Hodgkinson, C. Bankhead, S. Greenfield, C. Crawford, C. Heneghan, K. Khan, L. Locock, L.Hinton, C. McCourt, M. Selwood, N. Roberts, R. Stevens and R.J. McManus. Under Pressure: Can self-monitoring improve the detection of pre-eclampsia? (2013 poster).

Public involvement

We involved PPI from developing our initial application to dissemination of our findings.

We have found their input to be extremely useful and they have formed an integral part of our programme grant bid team.

Impact

We have shown that self-monitoring of blood pressure in pregnancy is feasible and could be used to improve the detection of raised BP during pregnancy. If shown to be successful, it would be applicable to many hundreds of thousands of individuals in the UK and beyond. We have used this data to develop a series of publication and to underpin a £2.5m programme grant application.

This project was funded by the National Institute for Health Research School for Primary Care Research (project number 171)

Department of Health Disclaimer

The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR School for Primary Care Research, NIHR, NHS or the Department of Health.