Dysfunctional uterine bleeding has multiple underlying causes but, at its root, the disease can be subdivided into ovulatory or anovulatory causes. Ovultaory bleeding occurs when there are underlying issues of ovulation. This may be due to ovarian dysfunction as well as hypothalamic axis disorders. Anovulatory causes are those that occur independent of ovulatory dysfunctions such as pregnancy, weight gain, endocrinopathies, and drugs. Idiopathic causes may also contribute to anovulatory dysfunctional uterine bleeding. Affected patients may affect with a range of uterine bleeding patterns such as menometrorrhagia, metrorrhagia, menorrhagia as well as inter menstrual spotting.

It can be classified as ovulatory or anovulatory, depending on whether ovulation is occurring or not.^[1]

• Uterine bleeding is deemed abnormal when there is an irregular amount or an irregular pattern of bleeding.
• Menometrorrhagia: Excessive and irregular bleeding between cycles and during menstruation
• Metrorrhagia: Irregular and more frequent bleeding
• Menorrhagia: Excessive, but regular bleeding

Ovulatory DUB happens with the involvement of ovulation, and may represent a possible endocrine dysfunction, resulting in menorrhagia or metrorrhagia. Mid-cycle bleeding may indicate a transient estrogen decline, while late-cycle bleeding may indicate progesterone deficiency. Ovulatory causes are associated with vascular disturbances.^[2]

Anovulatory cycle DUB happens without the involvement of ovulation. The etiology can be psychological stress, weight (obesity, anorexia, or a rapid change), exercise, endocrinopathy, neoplasm, drugs, or it may be otherwise idiopathic. anovulatory causes are associated with structural endometrial defects.^[3]