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Invented in 1958 by Dr. Edward H. Hon,〔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 )〕 a Doppler fetal monitor or Doppler fetal heart rate 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. Use of this monitor is sometimes known as Doppler auscultation. Doppler fetal monitors are commonly referred to simply as "Dopplers". 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. Originally intended for use by health care professionals, this device is becoming popular for personal use. However, the FDA recommends against their home use, citing possible harm to a developing fetus and that these should only be used under the supervision of a healthcare professional when medically indicated for the benefit of the health of mother and child. ==Fetal heart rates== Starting at week 5 the fetal heart rate accelerates by 3.3 bpm per day for the next month. The fetal heart begins to beat at approximately the same rate as the mother's, which is typically 80 to 85 bpm. The approximate fetal heart rate for weeks 5 to 9 (assuming a starting rate of 80): *Week 5 starts at 80 and ends at 103 bpm *Week 6 starts at 103 and ends at 126 bpm *Week 7 starts at 126 and ends at 149 bpm *Week 8 starts at 149 and ends at 172 bpm *At week 9 the fetal heartbeat tends to beat within a range of 155 to 195 bpm. At this point, the fetal heart rate begins to decrease, and generally falls within the range of 120 to 160 bpm by week 12.〔FetalSure. Fetal Heart and Heartbeat Facts. Available at http://www.fetalsure.com/fetal-heart.html. Retrieved 9 August 2010.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Doppler fetal monitor」の詳細全文を読む スポンサード リンク
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