Fetal heart sounds cannot be heard at 6 weeks of gestation, but can be heard through the abdominal wall at 12 weeks of gestation, and the normal fetal heart rate is between 110 and 160 beats. In early pregnancy, ultrasound can be done at about 6 weeks of menopause to clarify the intrauterine pregnancy, at this time can also see the fetal buds and the original fetal heartbeat, at this time only suggests that the fetal heartbeat is strong, but can not hear the fetal heart sound. At 12 weeks of gestation, fetal heart sounds can be heard through the abdominal wall by Doppler fetal heart stethoscope, and the normal fetal heart rate is between 110 and 160 beats per minute. At 18 to 20 weeks of gestation, fetal heart sounds can be heard through the abdominal wall with a normal stethoscope, and it is normal for fetal heart sounds to increase during fetal movement. In low-risk pregnancies, fetal heart rate monitoring can be ordered after 34 weeks of gestation to continuously observe the fetal heart rate and reflect the intrauterine condition of the fetus.