The technology could help doctors detect complications earlier in high-risk pregnancies. In one case during clinical testing, the patch detected prolonged abnormal fetal signals that prompted medical intervention through an early Cesarean delivery, which researchers say may have helped save the baby's life.

The technology could also expand access to prenatal care in low-resource settings, where skilled ultrasound technicians and continuous, long-term monitoring are often limited or unavailable.

The work is published in Nature Biotechnology.

"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 nano engineering Ph.D. student at the UC San Diego Jacobs School of Engineering.

Park co-led the study with fellow UC San Diego Jacobs School of Engineering co-first authors Yizhou Bian, Hao Huang and Sai Zhou.

How the wearable patch works

Currently, most prenatal ultrasounds typically provide only brief snapshots of fetal health and require trained sonographers to operate the equipment. The new wearable ultrasound patch is designed to stay on the body and continuously track a baby's anatomy and blood flow in real time, without requiring someone to manually guide the ultrasound probe.

"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," Bian said. "That is why the sensing depth, functional capabilities and autonomy of this ultrasound technology are critical."