Abnormal uterine bleeding may be characterized by excessive bleeding during the menstrual period (menorrhagia), by frequent and irregular bleeding (metrorrhagia), or a combination of both (menometrorrhagia). Dysfunctional uterine bleeding (DUB) is defined as abnormal endometrial bleeding without structural pathology.<sup>32 Polaneczky M.M., Slap G.B. Menstrual disorders in the adolescent: Dysmenorrhea and dysfunctional uterine bleeding Pediatr Rev 1992 ;  13 : 83-87  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Abnormal uterine bleeding may occur in women of all ages, and although precise figures are unavailable,<sup>30 Mitchell H., Medley G. Abnormal vaginal bleeding is common, malignancy rare [letter] Med J Aust 1995 ;  162 : 164-165

Cliccare qui per andare alla sezione Riferimenti</sup> it is a particularly common issue for adolescents. As many as 95% of cases of abnormal vaginal bleeding in adolescents are caused by DUB,<sup>7 Deligeoroglou E. Dysfunctional uterine bleeding Ann N Y Acad Sci 1997 ;  816 : 158-164  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> but the diagnosis of DUB remains a diagnosis of exclusion, and other potential causes must be investigated. Familiarity with the normal menstrual cycle is necessary to identify the possible causes of abnormal bleeding and aids in the diagnosis and treatment of patients with abnormal uterine bleeding.