What happened to the fetal heart rate after 30 weeks?

I am now 30 weeks pregnant, and the fetal heart rate has been relatively fast recently. May I ask why the fetal heart rate has been fast after 30 weeks?

After 30 weeks, the fetal heart rate has been fast, which is considered to be caused by fetal hypoxia in the uterine cavity. The fetal heart rate ranges from 110 to 160 beats. If the fetal heart rate is always fast, but the fetal heart rate is still within the normal range, it is a normal phenomenon, and pregnant women do not need to worry too much. If the fetal heart rate exceeds the normal range, the pregnant woman should go to the hospital for further examination and do abdominal B-ultrasound to understand the situation of the fetus in the uterine cavity. symptoms of oxygen.