Possible reasons for lower abdominal distention after catheterization include: catheter stenosis or blockage, catheter irritation of the bladder, and combined urinary tract infection. 1. Catheter stenosis or blockage: after the catheter is inserted into the bladder, there may be folding, or because of the formation of fractions in the urine can cause luminal stenosis or blockage, the urine can not flow smoothly through the catheter, and after reaching the upper limit of the bladder capacity, it can produce a feeling of distention in the lower abdomen. 2. Catheter irritation of the bladder: after the catheter is inserted into the bladder mucosa can produce a certain stimulation, there may be pain, bloating and other discomforts, usually after a period of time can be gradually adapted. 3. Urinary tract infection: catheterization increases the risk of urinary tract infection, usually the longer the catheter is in place, the higher the risk of infection. When urinary tract infection occurs, patients may have a series of bladder irritation symptoms, such as urinary frequency, urgency, bladder discomfort, lower abdominal distension. Patients with catheters who experience lower abdominal distention are advised to talk to their treating physician as soon as possible in order to identify the cause of the distention and treat it accordingly.