There are few sounds more reassuring to a pregnant woman than the sound of her baby’s heartbeat. While it is considered standard practice in obstetric medical practices to monitor both the mother’s and baby’s vital signs, using Doppler technology for medical purposes is a relatively new phenomenon.
Discovered in 1842 by Austrian physicist Christian Doppler, the phenomenon was first described as the change in wavelength of a wave for an observer as they move relative to the source of the wave. In other words, sound changes as a person moves closer to then away from the source of the sound. This change in sound waves explains why police sirens seem to change in pitch as they pass.
The Doppler effect was put into use by the military during World War I as submarines attempted to detect enemy warships in the water. However, the medical applications of the Doppler effect were already being explored as transducers that created ultrasonic waves were being created as early as 1880 in early ultrasound sonography efforts.
The earliest use of a fetal Doppler monitor is credited to Dr. Edward Hon who was one of the first to note that a continuous fetal heart rate could be detected through the use of an ECG machine. Today’s models use a hand-held transducer to detect fetal heart rate. Some models include a digital display that shows the fetus’s heart rate. Even though a fetal stethoscope can be used to achieve the same goal, fetal Doppler monitors are equipped with an audio output feature that allows those in the room to hear the heartbeat as well.
From table top models to smaller pocket-sized models, Edan Instruments, Huntleigh, Natus Neurology, Newman Medical and Summit Doppler brands offer a variety of fetal Doppler monitors at a variety of prices with a variety of features.