Currently, doctors primarily rely on intermittent measurements of fetal heart rate using ultrasound imaging from outside the pregnant person’s body. The new device, on the other hand, can be gently inserted through the same narrow port already used in fetal surgeries.

Once inside the uterus, the device maintains stable, gentle contact with the fetus to reliably track heart rate, heart rate variability, blood oxygen levels and temperature. In studies on a large animal model, the probe provided accurate, precise, clinical-grade measurements even as the uterus and fetus moved during surgery.