This chapter specifically addresses uterine bleeding resulting from alterations in the normal cyclical changes of the endometrium. This type of bleeding is commonly referred to as dysfunctional uterine bleeding (DUB). Clinically, DUB indicates ovulatory dysfunction. By definition, DUB excludes postmenopausal bleeding or bleeding caused by the presence of specific pathologic processes such as inflammation, polyps, hyperplasia, carcinoma, exogenous hormones, and complications of pregnancy.