What is causing our hamster to bleed around her rectum/?

Yesterday my wife noticed that our 2 year old female teddy bear hamster had been bleeding a little from around her rectum/l area. There are no changes in her behavior, eating, and sleeping patterns. She hasn't been lethargic. She's alert, active, and the same as she has been since we picked her up from the breeder. Any insight would be greatly appreciated.