A new pregnancy patch could provide crucial, 24-hour monitoring for high-risk moms.

For decades, ultrasounds have been the primary means of fetal monitoring, but now engineers at UC San Diego have designed a wearable patch that promises continuous, comprehensive insight into the health of mom and baby.

The flexible, adhesive-backed UPatch is applied to the woman’s abdomen to deliver up-to-the-minute information about blood flow in the fetus and umbilical cord. Roughly the size of a hand, the UPatch is connected to a computer that analyzes ultrasound data.

Published this week in Nature Biotechnology, clinical testing of the UPatch demonstrated its life-saving potential. In one case, the patch identified a severe placental dysfunction that led to an early Cesarean delivery, which researchers say may have saved the baby’s life.

“Wearable ultrasound technology has the potential to enable continuous prenatal monitoring and improve pregnancy outcomes in ways that were previously not possible,” said study co-first author Geonho (Tom) Park, a chemical and nanoengineering Ph.D. student at the UCSD Jacobs School of Engineering.

Park and his team collected monitoring data across 62 pregnancies — some were healthy, while others were considered high risk on account of gestational diabetes, preeclampsia, high blood pressure or abnormal fetal growth.

The UCSD researchers compared their findings to those from a standard ultrasound machine — the patch and the machine produced statistically equivalent results.

Further, while current ultrasound technology requires trained sonographers and provides only a snapshot of fetal health, the UPatch tracks fetal health continuously without a manual technician.

“To comprehensively monitor mothers and babies over the amount of time needed to catch complications like preeclampsia, you need a system that can work continuously and largely on its own,” said co-first author Yizhou Bian.

“That is why the sensing depth, functional capabilities and autonomy of this ultrasound technology are critical.”

Developing the patch posed significant challenges, as it required collecting and interpreting information from deep inside the uterus and providing imagery in a constantly fluctuating environment.

“We thought, ‘What if we target the ultrasound device onto the placenta, in the area where the umbilical cord attaches?’” Park said. “Even though everything is moving, there is some stability in the umbilical cord at that location.”

A key element of the design is an image segmentation algorithm that tracks the placenta-anchored end of the umbilical cord, enabling the device to provide consistent measurements despite changes in the positions of the mother and fetus.

Researchers are hopeful this technology could help doctors manage high-risk pregnancies and detect complications earlier. While they believe the patch will be used in hospital settings at the outset, they plan to develop a wireless version that would allow doctors to monitor patients when they’re at home.

The technology could also prove beneficial in low-resource settings where ultrasound technicians and long-term monitoring are not readily available.