Vital Sign Alert (VSA) Device: A Novel Device for Use in Pregnancy

A novel vital signs measurement device is ideal for low resource settings for timely intervention of illnesses during pregnancy

The main driving force behind developing a unique device called Cradle Vital Sign Alert (VSA)1 was the observation made of different clinical outcomes in maternity care for pregnant women in diverse countries around the world – high, middle and and low-income. Almost 99 percent of maternal deaths occur in low-income and middle-income countries because of lack of timely intervention for illnesses due to deprived access and lack of training in public health care settings. Vital signs measurement – especially blood pressure and heart rate – is the most critical assessment which is necessary to do in pregnant and postpartum women to recognize early signs of any ailment. This assessment can allow for timely intervention and prevention of any serious clinical outcome and thus reduce mortality and morbidity due to pregnancy. Obstetric hemorrhage is a condition in which blood pressure increases and causes severe bleeding and infections. This illness alone accounts for 60 percent pregnancy deaths worldwide. Hypertension, sepsis and complications from abortion are some other serious outcomes and all these conditions are preventable and directly related to abnormal vital signs.

Microlife Cradle Vital Sign Alert device

Cradle project of Microlife2 aimed to develop a device which can accurately detect abnormalities in pregnant women’s vital signs like blood pressure and heart rateand could be used in low-and-middle income countries in small community nursing homes, clinics and hospitals. This device would be evaluatedfor its ability to provide a fast referral and intervention. The Cradle VSA device can accurately measure both blood pressure and heart rate and using these it can calculate a women’s risk of developing shock by providing a maximized alert through its novel early warning system. This simple visual warning system is based on a traffic-light color system where green means no risk, amber means careful monitoring is required and red means emergency treatment is needed. The warning alerts assist in identifying conditions for which low-cost and simple standard treatments are available. The standard algorithm used for non-pregnant adults was improvised for pregnant women over a period of six years.

Ideal for low-and-middle income countries

The Cradle VSA device is the first ever to achieve WHO standards for use in low-resourced countries as itcosts only around 15 GBP per device. It consumes very little power and can be charged by any USB phone charger allowing up to 250 readings with one cycle of charge. It’s a robust, almost unbreakable and specially calibrated device which can withstand extreme temperatures, humidity and pressure. Clinical trials are ongoing in many low-and-middle-income countries1.

A study published in BMJ Innovations evaluated the usability and accessibility of this device in typical low resource settings3,4. One study was conducted in primary care settings in low or middle incomes countries of India, Mozambique and Nigeria and some hospitals in South Africa. 155 interviews within six focus groups were conducted in local languagesalong with audio recordings of pregnant women and their family members. This was followed by a thematic analysis after recordings were transcribed into English. Results showed that majority of healthcare workers found the device accurate and easy to use. The integrated traffic-light signal approach to warning was easily understood and well received while imparting confidence in less trained healthcare workers. This helped them in taking accurate and fastdecisions which were then taken forward as referrals or a form of treatment. Only very few workers reported that they were not comfortable with using the device when measuring vital signs in obese women and patients having hypertension.

The Cradle VSA is an innovative yet simple-to-use device which can make a strong impacton reducing annual pregnancy deathsin low-and-middle income countriesby almost 25 percent. By early and timely detection, pregnant women can receive medical care quickly providing a better outcome to soon-to-be-mothers and also to their unborn babies.


{You may read the original detailed paper by clicking the DOI link given below in the list of cited source(s)}


1. Cradle Innovation. [Accessed February 5 2019]

2. Microlife. 2019. Microlife Corporation. [Accessed February 5 2019]

3. Vousden N et al. 2018. Evaluation of a novel vital sign device to reduce maternal mortality and morbidity in low-resource settings: a mixed method feasibility study for the CRADLE-3 trial. BMC Pregnancy Childbirth. 18(1).

4. Nathan HL et al. 2018. The CRADLE vital signs alert: qualitative evaluation of a novel device designed for use in pregnancy by healthcare workers in low-resource settings. Reproductive Health.

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