Fetal heart is not just the heart of the fetus, but mainly refers to the heartbeat of the unborn fetus inside the mother’s uterus. Fetal heart can reflect the state of the fetus in the uterus, and will change accordingly when the fetus is deprived of oxygen for various reasons. Usually, the fetal heartbeat can be heard gradually from the 8th week of pregnancy. At this time, the fetal heartbeat is very soft and can only be heard by Doppler ultrasound, which is like the sound of a horse’s hooves or the rumbling of a train. Normal fetal heartbeat is regular and strong, usually between 110-160 beats/minute, with the different environment in the uterus, the fetal heartbeat is also changing. If the fetal heart rate is >160 beats/minute and lasts for more than 10 minutes, it is called fetal tachycardia, which alerts the fetus to the presence of intrauterine hypoxia, umbilical cord compression, etc., and requires prompt medical attention and fetal heart rate monitoring. If the fetus is full-term, the pregnancy can be terminated in time, if necessary, and if the fetus is not full-term, it is necessary to give dexamethasone to promote lung maturation and fetal heart rate monitoring. If the fetal heart rate is less than 110 beats per minute, it is called bradycardia, and the fetus may have hypoxia, fetal head pressure, high intrauterine pressure, congenital underdevelopment, etc. It is necessary to consult a doctor in time to clarify the cause of the disease and to treat the cause of the disease.