A major new study published today in The Lancet Obstetrics & Gynaecology and Women’s Health highlights the success of a simple maternity innovation in improving the quality of care across Sierra Leone at scale — while underscoring the urgent need to strengthen health systems to save more lives.
The CRADLE-5 trial, led by King’s College London in partnership with the Sierra Leone Ministry of Health and the Welbodi Partnership, is one of the largest maternal health implementation studies ever conducted in a low-income country. The trial tested the nationwide rollout of the CRADLE Vital Signs Alert device — a low-cost, pregnancy-validated blood pressure and pulse monitor with a traffic-light early warning system — across eight districts, covering half of Sierra Leone.
Between May 2022 and June 2023, more than 2,100 health workers were trained, and 2,171 CRADLE devices were distributed to 95% of government health facilities, supporting care for over 93,000 births. The study found that CRADLE significantly improved the frequency and accuracy of vital-sign monitoring, enabling earlier detection of complications such as haemorrhage, sepsis, and pre-eclampsia.
However, while these improvements enhanced detection and response to complications, the trial found no overall reduction in maternal deaths or stillbirths, revealing that technology alone cannot save lives without parallel investments in drugs, blood supplies, ambulances, and trained staff.
Dr Alexandra Ridout, Clinical Lecturer at King’s College London and co-chief investigator, added:
“Every number in this trial represents a mother and a baby. CRADLE empowers health workers to detect danger quickly — even when a woman feels well. But early warnings must be matched with action, and that means investment in drugs, staff and emergency systems. Technology works when the health system works.”
Professor Andrew Shennan, inventor of the CRADLE device, said:
“This trial demonstrates that research can be done where it is needed most — a phenomenal global collaboration.”
Dr Sartie Kenneh, Chief Medical Officer, Ministry of Health and Sanitation, Sierra Leone, said:
“Too many mothers are still dying from conditions we know how to detect and treat. Innovations like CRADLE are powerful tools, but their impact depends on medicines, trained staff, and functioning referral systems. By embedding CRADLE into our national health system, training frontline workers, we have shown what partnership can achieve — turning early warnings into lifesaving action.”
Mariama Momoh, midwife and public-health specialist involved in the rollout, said:
“CRADLE lets workers with even basic training make fast, informed decisions. It makes work easier and saves lives. By equipping facilities nationwide, we are bridging critical gaps in maternal and newborn care and moves us closer to ending preventable deaths.”
One mother of three from Kono District shared her story: “I was able to survive because of CRADLE. When the nurse used the CRADLE machine, the red light flashed. My blood pressure was very high — I felt fine, but the nurse sent me to hospital because of that light. They said I had pre-eclampsia and my baby had to be born. We both survived, thank God and I could go home to care for my other children. Without that machine, I wouldn’t have known anything was wrong.”
Descriptions of the CRADLE device by mothers whose lives were impacted by the use of the device indicate its lifesaving efficacy and impact: ‘Talk true’- cradle is always accurate and doesn’t lie; ‘Quick action’ – act fast in detection for prompt action and ‘Magic machine’.
Described by The Economist as a technology that could help save the lives of 200,000 women a year, CRADLE-5 offers the clearest evidence yet that such innovations can be scaled nationally and embedded sustainably. The challenge for the global health community is ensuring that early warnings are matched with the resources needed to act. The study’s findings make a strong case for global investment in maternal health systems that can match early detection with timely, effective treatment.
A link to the article in the Lancet can be found here.
- The CRADLE-5 trial was led by the Sierra Leone Ministry of Health and Sanitation and King’s College London, in collaboration with NGO Welbodi Partnership, UNICEF, and partners in the UK and Sierra Leone.
- Funded by the UK National Institute for Health and Care Research (NIHR) and UNICEF.
- Sierra Leone’s maternal mortality ratio is estimated at 443 deaths per 100,000 live births (UN, 2020).
- CRADLE devices cost less than £20 each and are validated for use in pregnancy, including in pre-eclampsia and haemorrhage.
