The fetal heart can be detected by ultrasound at around 45-50 days of gestation. If you listen to the fetal heart from the abdomen, it needs to be around 20 weeks of gestation. The fetal heart is mainly checked by ultrasound in the early stage. Usually the gestational sac can be seen by ultrasound around 6 weeks of pregnancy, and the germ and fetal heart can be seen around 7 weeks of pregnancy. After the gestational sac is found, the fetal heart can be developed in about 1 week. If there is still no fetal heart for more than 10 days, it should be fetal abortion and need to perform early abortion as much as possible. At about 20 weeks of pregnancy, the fetal heart can be heard from the abdomen by Doppler fetal heart auscultator. The normal number of fetal heartbeats is between 110 and 160 beats per minute, and the fetal heartbeat may be faster in early pregnancy. In the middle and late pregnancy, the average fetal heartbeat is about 140 beats per minute, and the fetal heartbeat can accelerate after fetal movement and can exceed 160 beats per minute for a short period of time. If the fetal heartbeat is too fast or too slow for 10 minutes in a row, it may be a sign of fetal hypoxia and should be taken seriously.