Atrophic Vaginitis: This condition is the most common cause of postmenopausal bleeding, resulting from the thinning and drying of the vaginal walls due to decreased estrogen levels. It is characterized by symptoms such as vaginal dryness, itching, and pain, in addition to bleeding.

Endometrial Hyperplasia: This condition involves the thickening of the lining of the uterus, which can lead to bleeding. It is more common in postmenopausal women and can be a precursor to endometrial cancer.
Endometrial Polyps: These are growths in the lining of the uterus that can cause bleeding. They are common in postmenopausal women and can be benign or malignant.
Hormone Replacement Therapy (HRT): Women on HRT may experience bleeding due to the hormonal effects on the uterus.

Endometrial Cancer: Although less common, endometrial cancer is a critical diagnosis to consider in postmenopausal bleeding. It often presents with vaginal bleeding and requires prompt investigation.
Cervical Cancer: Although less likely, cervical cancer can also cause postmenopausal bleeding. Regular screening can help in early detection.
Uterine Sarcoma: A rare but aggressive form of cancer that can present with bleeding.

Ovarian Cancer: While ovarian cancer can cause bleeding, it is less commonly associated with postmenopausal bleeding compared to other symptoms like abdominal bloating or pelvic pain.
Vaginal Cancer: A rare type of cancer that can cause bleeding, often associated with other symptoms like vaginal discharge or pelvic pain.
Uterine Artery Embolization: A procedure that can sometimes cause bleeding as a complication, though this would be in the context of a known history of the procedure.