First-Of-Its-Kind Probe Monitors Fetal Health in Utero During Surgery

Clinicians currently rely on intermittent ultrasound measurements of fetal heart rate taken from outside the pregnant person’s body, providing only partial and delayed information. Sudden drops in heart rate or oxygen levels can occur without warning, increasing the risk of fetal distress or cardiac arrest. Now, researchers have developed a device that enables continuous, real-time monitoring of multiple fetal vital signs directly inside the uterus.

The device, developed by researchers at Northwestern University (Evanston, IL, USA), in collaboration with Ann & Robert H. Lurie Children’s Hospital of Chicago (Chicago, IL, USA), is a soft, flexible, robotic probe designed to be inserted through the same narrow port already used in minimally invasive fetal surgeries. Once inside the uterus, the probe establishes stable, gentle contact with the fetus without damaging delicate tissues. Its hair-like form factor allows it to move naturally with the fetus and uterus while continuously measuring heart rate, heart rate variability, blood oxygen levels, and temperature throughout the surgical procedure.

The device was tested in a large animal model that closely mimics human fetal surgery conditions. During these studies, the probe delivered accurate, precise, clinical-grade measurements even as the fetus and uterus moved. Continuous multiparameter monitoring allowed earlier detection of physiological changes compared with standard intermittent ultrasound measurements. The platform, presented in in Nature Biomedical Engineering, represents the smallest device developed to date capable of accurately measuring fetal vital signs.

By providing continuous insight into fetal physiology, the device could significantly improve safety during fetal surgeries by enabling faster clinical responses to early signs of distress. Simultaneous tracking of multiple vital signs offers a more complete picture of fetal health than heart rate monitoring alone. The researchers aim to further validate the technology and advance it toward clinical use. In the future, this approach could become a standard tool in fetal surgery, helping clinicians maintain fetal stability and reduce complications during complex in-utero procedures.

“We also believe that these same types of probes could be used in the future to identify complications during the intrapartum period, for early interventions to reduce stillbirths and other adverse perinatal outcomes,” said Northwestern bioelectronics pioneer John A. Rogers, who led the device development.

Related Links:
Northwestern University
Ann & Robert H. Lurie Children’s Hospital of Chicago