Pain in the lower abdomen after holding urine is mainly related to overfilling of the bladder, elevated pressure, and overstretching of the bladder wall. Bladder function is regulated by the brain and spinal center, and normally the body produces urinary urge when about 200ml of urine accumulates in the bladder, and more than 400-500ml can cause the bladder forceps to fail to contract normally, affecting normal urinary function, at which time urine is retained in the bladder and the bladder wall expands, causing pain in the lower abdomen. In addition, holding a large amount of urine for a long time may also cause urinary tract infections. Mainly due to the bladder vascular wall pressure, overstretch, resulting in mucosal ischemia, thinning, when pathogenic bacteria from the urethra retrograde infection, into the bladder, kidneys cause urinary tract infection or even the development of urinary stones, hydronephrosis, pyelonephritis, the desire to urinate but can not be discharged, adding to the symptoms of lower abdominal distension and pain. For women, the enlarged bladder after holding urine may also squeeze the uterus in the pelvic cavity, causing the uterus to tilt back and shift, especially during menstruation, which may cause obstruction to the discharge of menstrual blood and cause pain in the lower back and abdomen. In addition, holding urine during pregnancy may also affect fetal development. The sudden emptying of the bladder and abdominal pressure after holding urine for a large amount of time may cause transient dizziness and even fainting and palpitations. And holding urine for a long time may also induce serious diseases such as bladder forceps weakness, elevated blood pressure, heart attack and stroke. Therefore, patients should avoid holding urine and empty the bladder in time, not to mention not drinking water or drinking less water in order to reduce the number of trips to the toilet. Although this reduces the number of urination, it is likely to result in concentrated urine and the accumulation of toxins and metabolic wastes, which is more likely to cause adverse effects such as urinary tract stones.