The Doppler Fetal Heart Monitor should be used in the exact location and in the correct position of the pregnant woman. To use the Doppler fetal heart monitor correctly, the location should be a quiet place where you can lie down, and the pregnant woman’s body position should be slightly higher than her head, with her legs stretched out in a relaxed state to facilitate the measurement of accurate values. Apply coupling agent on the probe to facilitate better fit of the probe and the body, and then look for the location of the fetal heart, generally in the chest or back of the fetus, you can through the pregnant woman’s belly for the detection of fetal heart rate, after tying up the monitor can be observed in the fetal heart rate situation. Fetal heart monitoring is to use ultrasound for detection, do not worry about the impact on the fetus.