The most common cause of urinary tract infections, specifically that of the bladder, is caused by bacterial growth. More often than not, the culprit bacteria causing UTI’s is E. coli. This bacterium is found in the digestive tract and is part of our natural flora, the healthy and helpful bacteria naturally found in or on the body. E. coli is passed with bowel movements and can easily be transferred from the anus to the urethra. Women are considerably more likely to develop a urinary tract infection, as the urethra is much shorter in females than males. In females, the urethra, the tube carrying urine from the bladder to the body's exterior to be expelled, measures about 1.5 inches long. Opposingly, a male's urethra measures around 7.5 inches. This extended length provides more protection of the bladder and kidneys, as it takes more effort and time for an infection to travel internally. Further, bacteria can easily migrate to a female urethra during back-to-front wiping, intercourse, tampon use, etc. During pregnancy, the pressure put on the bladder from the growing fetus and uterus disallows complete emptying of the bladder. If residual urine is stored longer than usual, bacterial growth will increase. Menopause can also lead to an increase in UTIs, as varying hormonal changes affect the state of the vaginal and urethral lining, making it weaker. In men, the cause of bladder infection is more often due to prostate infection. An enlarged prostate, in this case, has the same effect on the bladder as pregnancy does.