The fetal heartbeat is the number of times the fetal heart beats, and it can be heard with a stethoscope. Of course it requires some expertise and skill, by also needing a special stethoscope. But it needs to be fully heard at around 18-20 weeks of pregnancy, and some people may need to hear it a little later. There is a relationship with the thickness of the pregnant woman’s abdominal wall, the amount of amniotic fluid and the baby’s position. The primitive fetal heartbeat will appear around 8 weeks of pregnancy, but at this time it is too light to be heard with a stethoscope, and can only be detected by ultrasound or with a special Doppler fetal heart rate monitor. At 4 months of gestation, the fetal heart is basically well developed and the fetal heartbeat is stronger at this time, but it is difficult to hear with a normal stethoscope because the fetus is still relatively small. At 18 weeks or 4.5 months of gestation, an experienced obstetrician can hear the fetal heart through a stethoscope. In obese women, the muscle layer of the abdominal wall is thicker, so it may take 20 weeks or more to hear the fetal heart with a stethoscope. Pregnant women with more amniotic fluid may not be able to hear the fetal heart until after 20 weeks with a stethoscope. If the baby’s fetal position is not good, then it will also affect the time to hear the fetal heartbeat with the stethoscope. The normal fetal heartbeat time is 120-160 beats per minute. Individuals who use a stethoscope to listen to the fetal heart will have a certain degree of error, so it is best to go to the hospital to let a professional doctor to listen, or directly do ultrasound to monitor the fetal heart.