What is the most common cause of postmenopausal bleeding?

Postmenopausal bleeding is commonly associated with various causes, but endometrial cancer is the most significant reason for this symptom in postmenopausal women. After menopause, the endometrium, or lining of the uterus, undergoes changes primarily due to the decrease in estrogen levels. Although some benign conditions like uterine fibroids and atrophy of the vaginal tissues can cause bleeding, endometrial cancer presents a serious concern because it can indicate malignancy in this population.

In the context of postmenopausal women, any bleeding should be further evaluated to rule out endometrial cancer, as it has a higher incidence in this demographic than fibroids or other benign conditions. Hormonal therapy can sometimes cause bleeding due to the effects of estrogen on the endometrium, but such bleeding should also trigger an evaluation for cancer, as irregular bleeding is a common manifestation of endometrial cancer.

Therefore, given the significant implications and the need for diagnosis, endometrial cancer is recognized as the most common and concerning cause of postmenopausal bleeding that warrants thorough investigation.