Handheld foetal heartbeat monitor shows promise

Project Leader Neil Scott says that the new portable device, though still in prototype form, has the potential to be simpler, more convenient and more accurate than anything currently available on the market.

“This research offers to let pregnant mums frequently and simply check their babies’ heartbeat themselves,” he says.

“We have had considerable success to date in isolating the foetal heartbeat from the internal sounds of the mother, including digestion sounds and the maternal heartbeat, by using an array of sophisticated microphones embedded in a wide belt. We are now applying more complex sensor and processing technology to produce a handheld version.”

Both versions use a relatively new processing approach called Blind Source Separation, or BSS. This is a more passive alternative to the widely-used Doppler ultrasound device, called the SonicAid, which sends ultrasonic sound waves into the uterus. By using only microphones, the technique is more like that of the Pinard, the foetal stethoscope that midwives used before the invention of ultrasound.

The heartbeat of an unborn baby can give clues to its health throughout the pregnancy and be monitored before and during birth to give early warning of any problems. Although most clinicians believe ultrasound is perfectly safe, anecdotal evidence suggests that many mothers would like to reduce the degree of exposure to it and would also welcome the chance to monitor their babies’ heartbeat at home.

Senior project scientist Ranjan Acharyya is leading the development of the handheld equivalent of the heartbeat-monitoring belt, using a smaller sensor and an alternative form of processing. He says this may be possible by being more attuned to the specific sounds of the heartbeat and other noises.

“The sound environment within the mother changes all the time and many alternative techniques have failed because of this. We are hopeful that this current research will lead to better, more reliable products being available not just to clinicians but to all expectant mothers as well.”

The BSS project is part of a wider, established communications technologies research programme being run by IRL and implemented jointly with Victoria University’s School of Engineering and Computer Science.