Dysfunctional uterine bleeding (DUB) is abnormal genital tract bleeding based in the uterus and found in the absence of demonstrable structural[1] or organic pathology. It is usually due to hormonal disturbances: reduced levels of progesterone causes low levels of prostaglandin F2alpha and causes menorrhagia; increased levels of tissue plasminogen activator (TPA) (a fibrinolytic enzyme) leads to more fibrinolysis.
Diagnosis must be made by exclusion, since organic pathology must first be ruled out.
It can be classified as ovulatory or anovulatory, depending on whether ovulation is occurring or not.
Some sources state that the term implies a hormonal mechanism.[2] Use of the term "dysfunctional uterine bleeding" is currently discouraged in favor of the term "abnormal uterine bleeding.