The BuMP Pilot Study
This study aims to determine whether a programme to support women monitoring their own blood pressure through pregnancy is practical to implement, and acceptable. The study results will help us to develop schedules for self-monitoring and thresholds for the diagnosis of raised blood pressure in pregnancy based on the home readings.
Why this is important:
Self-monitoring of blood pressure in pregnant women has potential to be a successful approach in the detection of gestational hypertensive disorders (raised blood pressure) that include pre-eclampsia. (Hodgkinson et al., 2014)
Self-monitoring could be a more reliable way of detecting raised blood pressure in pregnancy, it could detect serious problems sooner or would avoid unnecessary medication. - Dr Katherine Tucker, University of Oxford.
Pre-eclampsia affects around 5% of pregnancies in the UK and is defined as high blood pressure combined with protein leaking into the urine. Pre-eclampsia 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.
The diagnosis of pre-eclampsia requires monitoring of blood pressure and urine, typically by midwives at intermittent 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. However a number of women in the UK develop pre-eclampsia within the interval between antenatal visits.
Regular monitoring of blood pressure and proteinuria would be reasonably expected to improve detection of pre-eclampsia in the high risk pregnant population. One solution is for women to monitor their own health through pregnancy, this would reduce the time, expense and inconvenience of frequent appointments without compromising the ability to detect and monitor a potentially serious disease.
We recently carried out a prospective observational study of self-monitoring of blood pressure in Oxfordshire and Birmingham. Patients were invited to participate if they are defined by the NICE guidelines as at higher risk of pre-eclampsia (NICE clinical guideline 62). This included women with any of the following risk factors:
- Age 40 years or older
- First pregnancy
- Pregnancy interval of more than 10 years
- Family history of pre-eclampsia
- Previous history of pre-eclampsia
- Body mass index (BMI) 30 kg/m2 or above at booking
- Pre-existing vascular disease such as hypertension
- Pre-existing renal disease
- Multiple pregnancy
201 participants were recruited from April 2013 to January 2014 and asked to measure their blood pressure morning and evening, three times a week.
Participants experiencing any symptoms of pre-eclampsia or recording a raised home reading (>140 SBP and / or 90 DBP mmHg), that did not settle when measured in triplicate, were advised to contact their midwife, GP or maternity assessment unit for clinic blood pressure and proteinuria testing as appropriate. Women were able to text their BP results which could be seen by the research team.
Read more about Florence: The NHS self-care service.
The acceptability and feasibility of this intervention has been assessed by participant questionnaires and interviews in a linked qualitative study that will be published as part of a module on pre-eclampsia on the Healthtalk.org in 2016
How this could benefit patients:
This preliminary work suggests that self-monitoring of BP during pregnancy is feasible and acceptable to women and that this intervention could improve the detection of raised BP during pregnancy.
We think that the higher risk population is most likely to be benefit from more frequent monitoring. Self-monitoring where individuals measure their own BP in a home setting, allows multiple measurements with little or no disturbance of lifestyle and is now commonplace in adults with hypertension. This could result in the earlier detection of serious disease with relatively little inconvenience or cost.
Assessment of blood pressure outside of a medical environment provides a more realistic estimation of blood pressure and is less intrusive than ambulatory BP monitoring. Self-monitoring could improve the detection of raised blood pressure in pregnancy and may represent a good way of differentiating white coat hypertension with true hypertension and thus avoid unnecessary medication during pregnancy.
We are now planning a large randomised control trial to test this intervention at a suitable scale.