Final answer:
The most common cause of postmenopausal bleeding is endometrial hyperplasia. This can be ruled out through an endometrial biopsy.
Step-by-step explanation:
The most common cause of postmenopausal bleeding is endometrial hyperplasia. This is a condition in which the lining of the uterus becomes thicker than usual. It can increase the risk of developing endometrial cancer. To rule out endometrial hyperplasia, an endometrial biopsy can be performed, in which a small sample of the uterine lining is taken and examined.