Pregnant women usually experience frequent urination during the first to third month of pregnancy and after the ninth month of pregnancy. Pregnant women are prone to frequent urination within 1-3 months of pregnancy, mainly because the uterus gradually increases in size after pregnancy, pressing on the bladder, resulting in a smaller bladder capacity, which leads to frequent urination, but generally with the increase in months of pregnancy, when the uterus increases beyond the pelvic cavity, the pressure on the bladder may be lifted, and then the symptoms of urinary frequency can be improved. But in the late pregnancy after 9 months, due to the head of the fetus into the pelvis, resulting in the pelvic floor is squeezed, thus re-inducing the pregnant woman bladder pressure, the symptoms of frequent urination. Frequent urination symptoms during pregnancy are generally not accompanied by urinary urgency, urinary pain and other symptoms of infection, simply due to physiological compression, but if there is urinary pain, abdominal pain and other phenomena, indicating the presence of other factors, the need for timely medical attention.