Updated: Dec 22, 2020
How Baby Fetal Heart rate Monitor Work?
A handheld baby heartbeat monitor or fetal Doppler uses a probe to detect the high-frequency sound waves produced by the baby’s heart using ultrasound technology. This device only uses low emission ultrasound technology. To magnify the sound waves and enable the probe to pick them up, conductors like gel or oil are recommended.
The Doppler probe sends out the high-frequency sound waves that pass through your skin and tissue and into your baby. When these waves encounter movement like your baby’s heartbeat, it bounces back to the device and the device translates the movement into sound. The sound is amplified through the monitor.
The monitors are regulated by the FDA and are approved for home use.
The drawback of this process is that it translates all the movements inside you into sound, including your baby’s kicks and hiccups, the air moving in your intestines, or the blood flowing in your arteries. It takes a lot of patience and practice to successfully distinguish a baby’s heartbeat from the other sounds inside you.
What should my baby's fetal heart rate be?
The average fetal heart rate is between 110 and 160 beats per minute. It can vary by 5 to 25 beats per minute. The fetal heart rate may change as your baby responds to conditions in your uterus.
A Doppler fetal monitor is a hand-held ultrasound transducer used to detect the fetal heartbeat for prenatal care. It uses the Doppler effect to provide an audible simulation of the heartbeat. Some models also display the heart rate in beats per minute (BPM). The use of this monitor is sometimes known as Doppler auscultation. The Doppler fetal monitor is commonly referred to simply as a Doppler or fetal Doppler. It may be classified as a form of Doppler ultrasonography (although usually not technically - graphy but rather sound-generating).
Baby Fetal Heart rate Monitor provides information about the fetus similar to that provided by a fetal stethoscope. One advantage of the Doppler fetal monitor over a (purely acoustic) fetal stethoscope is the electronic audio output, which allows people other than the user to hear the heartbeat. One disadvantage is the greater complexity and cost and the lower reliability of an electronic device.
The device was invented in 1958 by Dr. Edward H. Hon, Originally intended for use by health care professionals, this device is becoming popular for personal use.
Dopplers for home or hospital use differ in the following ways:
Probe type: waterproof or not. Waterproof probes are used for water births.
Probe frequency: 2-MHz or 3-MHz probes. Most practitioners can find the heart rate with either probe. A 3-MHz probe is recommended to detect a heart rate in early pregnancy (8–10 weeks gestation). A 2-MHz probe is recommended for pregnant women who are overweight. The newer EchoHeart 5-MHz transvaginal probes aids in the detection of fetal heart tones (FHT) early in pregnancy (6–8 weeks) and for patients who have a retroverted uterus or throughout pregnancy for FHT detection for women who are obese.
Heart rate display: some Dopplers automatically display the heart rate on a built-in LCD; for others, the fetal heart rate must be counted and timed by the practitioner.
A major advantage of being able to record and share the recording is that it can be emailed to a healthcare professional to be checked if there are any concerns about whether or not it is the fetus's heart rate and whether or not is normal. Typically, they work for about 12 weeks.
In response to increasing home usage of clinical fetal doppler systems, the FDA issued a formal statement recommending against at-home use. Baby Fetal Heart rate Monitor using 2-3MHz ultrasound are prescription devices designed and developed for use by licensed and trained health care professionals. System misuse (duration, angulation) and systems operating outside of the intended range can produce thermal and non-thermal effects on fetal tissue, including the possibility of over-heating fetal tissue and introducing mechanical stress on the fetus due to cavitation, radiation force, and acoustic streaming.
Can fetal heart monitors harm the baby?
The safety of the Doppler ultrasound devices is stressed, in that they do no harm to the baby, but the risks of delaying seeking medical attention and the limitations of Doppler devices tend to be overlooked. Current practice Movements can vary considerably from fetus to fetus and at different times of the day