Fetal heartbeat is the heartbeat of the fetus, which is usually visible by ultrasound at more than 6 weeks of pregnancy and close to 7 weeks. Fetal heart sounds can be detected with a Doppler fetal heart stethoscope through the abdominal wall of a pregnant woman at 12 weeks of gestation; however, if the pregnant woman has a lot of abdominal fat, the fetal heart will be heard relatively late. Normal fetal heartbeat changes with the different environment in the uterus, and the change of fetal heart rate is the performance of the normal regulation of the central nervous system, and is also a sign that the fetus is in good condition in the uterus. Usually, the fetal heart sound is double tone, the first tone and the second tone are close to each other, like the ticking sound of a clock, and the speed is fast, 110-160 times per minute. When the fetus has intrauterine hypoxia due to various reasons, the fetal heart will change very sensitively. In addition, fetal heart monitoring is an important clinical method to determine the intrauterine safety of the fetus, and it is recommended to do regular checkups to observe the fetus.