High and low blood pressure in late pregnancy may be caused by exercise, mood swings and uterine contractions. 1. Exercise: for example, after walking and other exercises, the blood circulation of pregnant women will be accelerated, resulting in increased blood pressure, after resting, the blood pressure may return to its original value, so there will be high and low blood pressure. 2. Emotional fluctuations: If a pregnant woman is agitated and irritable in late pregnancy, it will easily lead to an increase in blood pressure. After calming down, the blood pressure will naturally drop. Therefore, the phenomenon of high and low blood pressure will occur. 3. Uterine contractions: Because uterine contractions are more frequent in late pregnancy, they affect the blood circulation around the uterus, which in turn affects the blood circulation of the whole body. Therefore, when uterine contractions are more frequent, the phenomenon of high and low blood pressure in late pregnancy may occur. During pregnancy, you should pay attention to more rest, and at the same time, you should relax and avoid tension and anxiety, if the blood pressure of pregnant women in late pregnancy is high and low, and the blood pressure fluctuates greatly. It is recommended to go to the hospital in time, follow the doctor’s instructions to take the appropriate medication, and try to rest in bed.