There is no clinical term for what fetal heart rate is a boy, because there is no relationship between the sex of the fetus and the fetal heart rate, which is mainly related to the fetal activity. If the fetus is more active, the fetal heart rate may be faster. If the fetus is at rest, the fetal heart rate will be relatively slow. However, as long as the fetal heart rate is between 120-160 beats per minute, it is normal. Moreover, China’s laws and regulations clearly stipulate that fetal sex determination is strictly prohibited for non-medical reasons, so the fetal heart rate cannot be used to determine the sex of the fetus. Usually, the fetal heart rate will change as the gestation period lengthens, generally at 5 weeks of pregnancy, the fetal heart rate is close to the mother’s heart rate, i.e. 80-85 beats/min. At 9 weeks of gestation, the heart rate gradually increases to 170-200 beats per minute, and then gradually slows down to 120-160 beats per minute in the middle of pregnancy. At around 18 weeks of gestation, the resting fetal heart rate tends to be 150 beats per minute, and by 38 weeks of gestation, the fetal heart rate is mostly at 140 beats per minute. If the examination reveals abnormal fetal heart rate, it is recommended to do fetal heart monitoring in time to check whether the fetus has hypoxia or whether the umbilical cord is under pressure, and to determine whether the fetus is in a normal state according to the fetal heart monitoring. If necessary, ultrasound is performed to detect the umbilical blood flow ratio of the fetus and to detect the general condition of the fetus to avoid adverse consequences.