What causes postmenopausal bleeding?

Postmenopausal bleeding, may be caused by malignant tumors, can be observed more bleeding, such as bleeding time is short, benign majority, do not need special treatment, but if bleeding time is long, it may be malignant tumor, need to go to the hospital immediately for examination. Also does not rule out is caused by cervical lesions, need to go to the hospital immediately for examination, exclude endometrial lesions. At the same time, also through B ultrasound examination, judge whether there is organic lesions.