Low urine output, or no urine output, occurs in the setting of kidney failure as well as in urinary obstruction. As the kidneys fail or become compromised in their ability to function, the kidneys lose the ability to regulate fluids and electrolytes and to remove waste products from the body. Additionally, red blood cell production (which is normally driven by a substance produced in the kidneys) decreases. Low urine output also occurs when there is a decreased blood supply to the kidney, such as occurs with dehydration or excessive blood loss. Obstruction of outflow of the urine, either due to tumors, enlargement of the prostate, or bladder problems can also reduce urine output. Reduced urine output as a result of kidney failure can be acute, as with toxins or sepsis, or chronic. Chronic renal failure develops over time and can result from poorly controlled diabetes or hypertension.