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A fingernail-size gadget could help prevent babies from being stillborn

an image of a pregnant woman's bellyan image of a pregnant woman's belly

Researchers have published a pilot study that introduces a new at-home, wearable device that could cut down on some of the 2.6 million stillbirths that occur every year around the world.

How does it work? The sensor is the same kind that reorients your smartphone’s screen when it detects motion. Chenxi Yang and Negar Tavassolian at Stevens Institute of Technology adapted that technology and embedded it in a small wearable patch. The result is kind of like a tiny seismograph: the fetal heartbeat causes the maternal abdomen to vibrate, which the sensor picks up on.

How accurate is it? Not perfect, but not too bad. Tavassolian said the accuracy rate on 10 pregnant women who wore the patch at NYU’s Langone Medical Center hovered around 80%—the team wants that rate to be closer to 99%. But it’s comparable to the accuracy of the electrode-based fetal cardiotocograms used in hospitals, the standard procedure for detecting fetal heart rate in expecting women.

Stillbirths often occur without warning. About one-third of all stillbirths happen without any previous complicating factors. Wearing a device like this could send women to the doctor at the earliest sign of trouble, which could in many cases save the fetus.

It’s part of a race to stop stillbirths. There are other products vying to get FDA approval to spot stillbirths before they happen. One is the Owlet, which uses an electrode band to track and record fetal heartbeat. Another is Rubi, which uses nanotechnology to track voltage changes in the fetus and then sends them to a smartphone. 

How is this different? Yang and Tavassolian said their product is cheaper (less than $100), rechargeable (battery life is about 24 hours), and easier to use, without the bulky electrodes that hospitals use. 

This might go beyond tracking fetal heart rate and preventing stillbirths. Any expecting mom could, in theory, wear the device, and Tavassolian said the goal is for it to be used as early as possible. That means that it might also help track proper growth and movement of the fetus to help prevent other complications, making it potentially useful in tracking the health of both the unborn baby and the pregnant woman.