Community Blood Pressure Monitoring in Rural Africa: Detection of Underlying Pre-Eclampsia (CRADLE)

Every year 287,000 women die in pregnancy and childbirth. Another 7-10 million suffer severe or long lasting illness or disability as a result of complications. 99% of these deaths are in developing countries.  162,000 (56%) occur in Sub Saharan Africa.

Pre-eclampsia and eclampsia (high blood pressure in pregnancy and around the time of birth) is a major cause of maternal mortality and can also lead to the deaths of foetuses and babies with an estimated fatality of 7-25% in African countries.

At present blood pressure (BP) monitoring is frequently unavailable in many rural African health clinics and community settings. However BP monitoring would provide a cheap screening tool as part of antenatal care. Once pre-eclampsia can be identified then effective interventions, such as induction or providing anti-hypertensive drugs and magnesium sulphate, are inexpensive and generally available at referral centres.

Of the 287,000 women who die each year in pregnancy and childbirth, 10-15% are estimated to be due to pre-eclampsia and eclampsia (high blood pressure)

CRADLE is a research study funded by the Gates Grand Challenge Explorations Fund and the Medical Research Council. Phase I and 2 have now been completed. The study so far has assessed the impact of introducing a cheap, automated, blood pressure monitor into rural antenatal clinics and amongst community health workers alongside basic training in its use and implications. It examined the effect this had on the numbers of suspected pre-eclampsia cases made to referral centres. These results will be used to inform Phase 3 with a preliminary trial now underway and starting in March 2016 a large scale clustered, randomised control trial to assess the full impact on mortality and morbidity levels amongst mothers and babies.

Of the 287,000 women who die each year in pregnancy and childbirth, 10-15% are estimated to be due to pre-eclampsia and eclampsia (high blood pressure)


Initial  research was carried out in 11 rural antenatal clinics in the Muheza district of Eastern Tanzania. 4 out of 11 had no blood pressure monitors and the remaining 7 had broken devices. Both solar and battery powered BP monitors were introduced and staff satisfaction with the different devices was measured.

Staff made good use of the devices and quickly found them easy and reliable to use and commented that other clinics would benefit from having the BP monitors.

‘We love it – at first we were worried, but it’s very simple to use and also much better compared to other machines we have had’  (member of clinical staff, Tanzania)

Originally it had been intended to focus on the development of solar powered devices. But it was found these required long charging periods and were perceived as less reliable by staff. For the next stage of the work the team therefore developed a standard machine specifically for use in low resource settings. This had the advantage of generating a reliable result with little training and had a prolonged battery life making it more efficient to use.

The next stage of the study was carried out in Tanzania (Kilimanjaro Christian Medical Centre and Hospitali Teule Muheza), Zambia (Ndola Hospital), Zimbabwe (Morganster Mission Hospital and Ethiopia (Gimbie Adventist Hospital). The objective was to measure whether the introduction of novel, low cost, easy to use BP devices alongside basic training would increase detection and referral of suspected pre-eclampsia to a secondary level referral hospital.


Use of the new BP monitor led to more women being identified with dangerously high blood pressure in the rural antenatal clinics and increased the number of referrals made to central hospitals for the treatment of hypertension. There was a significant reduction in patients who were seen centrally who had never had their BP checked in pregnancy.

One of the findings of the research was that even when a diagnosis of pre-eclampsia was made, women often could not access the care they needed because of financial, access or social barriers. CRADLE was only able to measure the effects on those women who were able to access the next level of care.  For this reason the team are collaborating with a trial to assess management of pre-eclampsia in a community setting. This will involve a multi-centre trial to definitively test the CRADLE intervention in combination with community based care for pre-eclampsia and referral mechanisms to access secondary care. This will in addition look at the impact on important maternal and fetal clinical outcomes.