The Doppler Fetal Monitor, also called a Doppler Fetal Heart Rate Monitor and baby heartbeat monitor, is the invention of Dr. Edward H. Hon. It is a lightweight, portable hand-held ultrasound device designed to help detect the developing baby’s heartbeat in the uterus during the pre-natal care period as well as during labor. Prior to its development in the 1950s, the growing fetus’ heartbeat could only be detected by a doctor or nurse placing a stethoscope on the mother’s stomach.
The Doppler Fetal Monitor gets its name from the Doppler effect, the change in a wave’s frequency when an individual moves in relation to the wave’s source. The sounds of the baby’s heartbeat are transmitted either through earpieces attached to the device or via an audio port that enables everyone in the room to hear the results. An advantage to using a baby heartbeat monitor in preference to an acoustic fetal stethoscope is that people other than the individual using the unit can all hear the sound of the heartbeat. Although originally intended as a professional device for obstetricians and other healthcare providers, the baby heartbeat monior has gained in popularity for personal usage by expectant mothers.
Fetal heart rates can be detected by the fifth week of pregnancy at a rate of 3.3 beats daily, although the fetal doppler may not accurately detect the fetus’ heartbeat until the 12th week of development. It can detect a variety of potential problems, including fetal diseases and infections, placental diseases, cord compression, and natural hypotension.
Some advantages to using a heartbeat monitor is that it requires very little training to operate properly, involves the live participation of a healthcare professional and doesn’t limit the mother’s movement during its usage. It is also easy to use during labor and contractions.
In recent years, there has been increased marketing of Doppler Fetal Monitors for use by the mother at home, either for purchase (around $400) or leased on a monthly basis ($25) , primarily for peace of mind in knowing that the baby’s development is proceeding normally. Some home units even allow for the heartbeat sounds to be recorded and subsequently downloaded onto a computer and saved for posterity. A special gel or lotion formula for use with the device is rubbed onto the mother’s abdomen in the area just under the pubic bone and the Doppler probe is moved around at different angles until the Monitor displays the number of heartbeats per minute and the sound of the fetus’ heartbeat can be clearly heard.