The fetal heart sounds can be heard with a normal stethoscope through the abdominal wall of the pregnant woman during 18-20 weeks of gestation, and the fetal heart sounds are binaural, resembling the ticking sound of a clock, with a fast speed, 110-160 times per minute at normal. The fetal heart sounds should be distinguished from uterine murmur, abdominal aortic murmur and umbilical cord murmur. The correct position is the middle of the lower umbilicus and the left and right sides of the umbilicus, if it is breech, it is the middle of the upper umbilicus or the left and right sides of the umbilicus. When listening to the fetal heart sounds, let the pregnant woman lie flat, you can first check the dorsal side of the fetus in what part, and then use the stethoscope to the abdominal wall of the pregnant woman, you can hear the fetal heart sounds.