Benign prostatic hyperplasia (BPH) or prostate enlargement is a non-cancerous swelling of the prostate gland. It is a common urological disorder in men over 50 years old. The swelling of the prostate causes the urethra (the tube that passes urine out of the penis) to be narrowed. This blocks urine flow out of the bladder, such that more pressure is required to urinate.
The bladder starts to tense and contract even when it is not completely full, eventually losing its ability to empty itself. The symptoms of BPH are linked to the narrowing of the urethra and the incomplete emptying of the bladder.