It is not true that the fetal heart can tell the sex of the fetus. The sex of the fetus is determined from the moment the fertilized egg is formed, depending on the type of sex chromosome of the fetus, if it is XX, it is a girl, if it is XY, it is a boy. Fetal heart refers to the heart rate of the fetus, the speed of the fetal heart rate can reflect the condition of the fetus in the uterus, whether there is a lack of oxygen in the uterus, but can not reflect the chromosome type of the fetus, so the fetal heart to see the male and female is not true. Under normal circumstances, the fetal heart rate is 110-160 beats per minute, if there is intrauterine hypoxia, the fetal heart rate can be increased in the early stage, and in the late stage, the fetal heart rate can be slowed down, and in severe cases, it can lead to fetal death in the uterus. Therefore, pregnant women should be timely checkups, the emergence of fetal heart rate abnormalities in a timely manner to seek medical treatment, so as to avoid delays in the condition leading to adverse consequences.