The normal value of fetal heart rate at 16 weeks of pregnancy is usually 110-160 beats/min, with a mean value of 144 beats/min. A normal fetal heart rate generally indicates that the fetus is moving well in the uterus and that there are no abnormalities in the transmission of blood and oxygen to the placenta. If the fetal heart rate exceeds 160 beats per minute, it is called tachycardia; if it is less than 120 beats per minute, it is called bradycardia. If both tachycardia and bradycardia persist for more than 10 minutes, it indicates the onset of intrauterine distress, which can lead to fetal growth retardation. The abnormal fetal heart rate may be related to the sleeping position of the pregnant woman in early pregnancy. The pregnant woman can try to change the left side lying position to increase the blood flow of the placenta and then observe whether the fetal heart rate will return to normal. If there is no remission, combined with organ structural or functional abnormalities, suggesting that there may be chromosomal variants, timely amniocentesis or non-invasive DNA testing is required, and conservative treatment or termination of pregnancy can be chosen under the guidance of the doctor. In the middle of pregnancy, pregnant women can test their own fetal heart by stethoscope at home. The pregnant woman is placed in a supine position with her head slightly elevated to expose her abdomen and her legs straight. The examiner stands on the right side of the pregnant woman, puts the stethoscope under the umbilicus of the pregnant woman slightly to the left or right, carefully and slowly move back and forth, can hear the clock “ticking” sound, faster, that is, the fetal heart rate, can listen to 2-3 times a day until delivery.