Holding urine during pregnancy may cause the stomach to harden. Excessive holding of urine during pregnancy causes the bladder to enlarge and compress the uterus leading to uterine contraction, which is characterized by mechanical stimulation and contraction. Do not hold urine often during pregnancy. In addition to the pressure on the uterus, holding urine often may cause urinary frequency, urinary urgency and pain due to urine accumulation in the bladder for too long and urinary tract infection, which may affect bladder function over time. During pregnancy, we should pay attention to the habit of timely urination. The enlarged uterus presses on the bladder in early pregnancy and the fetal head into the pelvis presses on the bladder resulting in physiological urinary frequency.