AFetal Doppler – NSL800C33/34is a hand-heldultrasoundtransducer used to detect thefetal heartbeatforprenatal care. It uses theDoppler effectto provide an audible simulation of the heart beat. Some models also display theheart rate每分钟节拍(BPM)。使用的监控sometimes known asDopplerauscultation. The Doppler fetal monitor is commonly referred to simply as aDopplerorfetal Doppler. It may be classified as a form ofDoppler ultrasonography(although usually not technically-graphybut rather sound-generating).

Doppler fetal monitors provide information about the fetus similar to that provided by afetal 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.

It was recently demonstrated that continuous Doppler enables theauscultationofvalvular movementsand blood flow sounds that are undetected during cardiac examination with a stethoscope in adults. The Doppler auscultation presented a sensitivity of 84% for the detection ofaortic regurgitations, while classic stethoscope auscultation presented a sensitivity of 58%. Moreover, Doppler auscultation was superior in the detection of impaired ventricular relaxation Since the physics of Doppler auscultation and classic auscultation are different, it has been suggested that both methods could complement each other.