Wearable Ultrasound Patch and Robotic Probe Offer New Options for Continuous Fetal Monitoring

Two separate research groups have published studies detailing new medical devices designed to provide continuous monitoring of fetuses. One device is a wearable ultrasound patch for prenatal monitoring, while the other is a robotic probe intended for use during fetal surgery.

Wearable Ultrasound Patch for Prenatal Monitoring

A Continuous Eye on Unborn Babies

Engineers at the University of California San Diego have developed a soft, wearable ultrasound patch, referred to as UPatch, that can monitor a fetus continuously for extended periods. The device uses autonomous tracking algorithms to follow the fetus and the umbilical cord as they move. The patch tracks fetal heart rate, contractions, and blood flow in real time.

The patch detected severe intrauterine growth restriction in a pregnancy with preeclampsia, leading to a cesarean delivery.

The device was tested in a multi-center clinical study involving 62 pregnancies across Jacobs Medical Center at UC San Diego Health and the John Radcliffe Hospital at the University of Oxford. Measurements from the patch reportedly showed close agreement with those from standard handheld ultrasound devices.

In one case involving a pregnancy with preeclampsia, the patch detected severe intrauterine growth restriction. According to the researchers, this detection led to a cesarean delivery. A different pregnancy resulted in a delivery at 29 weeks after the patch detected prolonged abnormal fetal signals.

Researchers noted that the patch’s continuous monitoring revealed dynamic fluctuations in fetal blood flow that could be missed by intermittent scans.

The study was published in Nature Biotechnology on May 26. The work was co-led by Geonho (Tom) Park, Yizhou Bian, Hao Huang, and Sai Zhou, all PhD students at UC San Diego Jacobs School of Engineering. The research builds on work in the laboratory of chemical and nano engineering professor Sheng Xu. On November 1, 2025, Xu moved his primary academic affiliation to Stanford University.

The current device is a proof-of-concept system that is tethered to external electronics and requires traditional ultrasound for initial placement. The team is developing a wireless version intended for use at home.

• Funding was provided by Wellcome Leap (HER01430), NIH (1R01EB033464-01 and 1R01HL171652-01), and Accelerating Innovation to Market at UC San Diego.
• Disclosures: Sheng Xu is a cofounder of Softsonics LLC. Maria Tome, Lawrence Impley, and Antoniya Georgieva are cofounders of Safer Birth LTD. Aris T. Papageorghiou is a Senior Scientific Advisor of Intelligent Ultrasound Ltd. Other authors declare no competing interests.

Robotic Probe for Fetal Monitoring During Surgery

A New Tool for the Most Delicate Surgeries

Researchers at Northwestern University have developed a soft, flexible, robotic probe for continuously tracking a fetus’s vital signs during minimally invasive fetal surgery.

The device is a filament-like probe, approximately three times the diameter of a single hair.

The device is designed to be inserted through the existing narrow port used in fetoscopic procedures. Once inside the uterus, the probe maintains stable contact with the fetus to monitor heart rate, heart rate variability, blood oxygen levels, and temperature.

The probe is a filament-like device, approximately three times the diameter of a single hair. It incorporates soft robotic actuators for positioning and a tiny, inflatable balloon-like cushion to maintain contact with the fetus. Miniature sensors transmit data wirelessly to an external monitor.

The researchers aimed to create a monitoring system that provides continuous, multi-parameter data without requiring additional invasive access.

A study on the device was published in Nature Biomedical Engineering. Tests were conducted on a large animal model. According to the researchers, the device delivered accurate, clinical-grade measurements despite uterine and fetal movement during surgery.

The device was co-led by John A. Rogers and Dr. Aimen Shaaban, a fetal surgeon at Ann & Robert H. Lurie Children's Hospital of Chicago.

Fetal surgery is performed in rare cases to address congenital conditions such as spina bifida, severe diaphragmatic hernias, and twin-to-twin transfusion syndrome. Fetoscopic procedures, which are less invasive than open fetal surgery, can complicate fetal monitoring. Current methods primarily rely on intermittent ultrasound imaging.