Doppler fetal monitor

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Doppler fetal monitor
Purposehear fetal heartbeat

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 heart beat. Some models also display the heart rate in beats per minute (BPM). 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).

Contents

Doppler fetal monitors provide 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.[ citation needed ]

The device was invented in 1958 by Dr. Edward H. Hon, [1] Originally intended for use by health care professionals, this device is becoming popular for personal use.

Types

Fetal Heart Rate and Activity Monitor - Baby Doppler Sonoline B by Baby Doppler .jpg
Fetal Heart Rate and Activity Monitor - Baby Doppler

Dopplers for home or hospital use differ in the following ways:

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 from about 12 weeks. [2]

In response to increasing home usage of clinical fetal doppler systems, the FDA issued a formal statement recommending against at-home use. [3] Fetal dopplers 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 intended range can produce thermal and non-thermal effects on fetal tissue, including the possibility for over-heating fetal tissue and introducing mechanical stress on the fetus due to cavitation, radiation force, and acoustic streaming. [4] [5]

See also

Related Research Articles

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Velamentous cord insertion is a complication of pregnancy where the umbilical cord is inserted in the fetal membranes. It is a major cause of antepartum hemorrhage that leads to loss of fetal blood and associated with high perinatal mortality. In normal pregnancies, the umbilical cord inserts into the middle of the placental mass and is completely encased by the amniotic sac. The vessels are hence normally protected by Wharton's jelly, which prevents rupture during pregnancy and labor. In velamentous cord insertion, the vessels of the umbilical cord are improperly inserted in the chorioamniotic membrane, and hence the vessels traverse between the amnion and the chorion towards the placenta. Without Wharton's jelly protecting the vessels, the exposed vessels are susceptible to compression and rupture.

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<span class="mw-page-title-main">Phonocardiogram</span>

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<span class="mw-page-title-main">Circumvallate placenta</span> Medical condition

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Amnioinfusion is a method in which isotonic fluid is instilled into the uterine cavity.

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<span class="mw-page-title-main">Doppler ultrasonography</span> Ultrasound imaging of the movement of tissues and body fluids using the Doppler effect

Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids, and their relative velocity to the probe. By calculating the frequency shift of a particular sample volume, for example, flow in an artery or a jet of blood flow over a heart valve, its speed and direction can be determined and visualized.

References

  1. Roger K. Freeman, Thomas J. Garite, Michael P. Nageotte, Fetal Heart Rate Monitoring Third Edition, 2003, p. 3. "The earliest preliminary report of FHR monitoring came in 1958 from Edward Hon, MD,... via fetal ECG monitor on the maternal abdomen." Google Books citation
  2. Dawes, G. S. (September 1981). "Numerical analysis of the human fetal heart rate: The quality of ultrasound records". American Journal of Obstetrics and Gynecology. 141 (1): 43–52. doi:10.1016/0002-9378(81)90673-6. PMID   7270621 via AJOG.
  3. Vaezy, Shahram (December 2014). "Avoid Fetal "Keepsake" Images, Heartbeat Monitors". U.S. Food & Drug Administration. Retrieved September 12, 2018.
  4. Church, Charles (April 2007). "Quantification of risk from fetal exposure to diagnostic ultrasound". Progress in Biophysics and Molecular Biology. 93 (1–3): 331–353. doi:10.1016/j.pbiomolbio.2006.07.015. PMID   16949653.
  5. Edwards, M.J. (July 2009). "Effects of heat on embryos and foetuses". International Journal of Hyperthermia. 19 (3): 295–324. doi:10.1080/0265673021000039628. PMID   12745973. S2CID   23521342.