What device is specifically described as a handheld tool that detects fetal heart sounds?

The Doppler fetal monitor is a handheld device specifically designed to detect fetal heart sounds. It uses the Doppler effect to produce sound waves that bounce off moving objects, such as a fetus's heart, and converts these sound waves into audible heart tones. This allows healthcare providers to listen to and assess the fetal heart rate conveniently.

In contrast, an electronic fetal monitor typically includes larger and more complex machinery that often requires setup on a hospital bed and is used to provide continuous electronic monitoring of both fetal heart rate and uterine contractions. An ultrasound scanner is primarily used for imaging and visualization of the fetus and internal structures rather than solely for heart sound detection. A cardiotocograph combines both fetal heart rate monitoring and uterine activity and is also not handheld, making it distinct from the more portable Doppler fetal monitor.