Fetal heart rate decreases as the weeks of the fetus get older, which may be caused by normal physiological fluctuations, lowering of the position of the fetal heart, intrauterine hypoxia, or fetal dysplasia, etc., and needs to be analyzed specifically. 1. Normal physiological fluctuations: under normal circumstances, the fetal heart itself fluctuates and is not constant, as long as it is within the normal range of gradual decline, there is no need to be too nervous. 2. Decrease in fetal heart position: with the increase in the number of days of pregnancy, the position of the fetal heart also decreases after the fetus is in the pelvis, and then the fetal heart rate will decrease, which is also a normal physiological phenomenon. 3. Fetal intrauterine hypoxia: fetal heart is getting lower and lower, may also be caused by fetal intrauterine hypoxia, usually occurs in late pregnancy, if the baby’s fetal heart rate is lower than the normal range, that is, lower than 110 beats / min, we should highly suspect that there is fetal distress. 4. Fetal dysplasia: If the fetal heart rate is persistently low, it may also be caused by embryonic dysplasia, because the fetus itself has problems, so the fetal heart rate will naturally be affected. If there is a decrease in fetal heart rate, you need to consult a doctor in time to clarify the specific cause, and take appropriate methods to deal with it according to the cause of the disease.