Practice bulletin no. 136: management of abnormal uterine bleeding associated with ovulatory dysfunction.

OBSTETRICS & GYNECOLOGY Background Definition and Nomenclature Abnormal uterine bleeding associated with ovulatory dysfunction (AUB-O) (ie, oligo-ovulation or anovulation) is a spectrum of disorders most commonly associated with heavy, irregular uterine bleeding. Abnormal uterine bleeding (AUB) occurs in the setting of ovulatory dysfunction because of the effects of chronic unopposed estrogen on the endometrium. Abnormalities at any level of the hypothalamic–pituitary–ovarian axis can result in interruption of the ovulatory cycle. Recognized causes of anovulation are listed in Box 1. In an effort to create a universally accepted system of nomenclature to describe uterine bleeding abnormalities in reproductive-aged women, an alternative classification system (polyp, adenomyosis, leiomyoma, malignancy and hyperplasia, coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not yet classified), known by the acronym PALM–COEIN, was published in 2011 by the International Federation of Gynecology and Obstetrics (FIGO) (Box 2) and adopted by the American College of Obstetricians and Gynecologists (2). The PALM– COEIN system classifies uterine bleeding abnormalities by bleeding pattern and etiology. The overarching term AUB is paired with descriptive terms to denote bleeding patterns associated with AUB, such as heavy menstrual bleeding (instead of menorrhagia) and intermenstrual bleeding (instead of metrorrhagia). Abnormal uterine bleeding is further classified by one (or more) letter qualifiers that indicate its etiology (Box 2). The term dysfunctional uterine bleeding––often used synonymously with AUB in the literature to indicate AUB for which there was no systemic or locally definable structural cause––is not part of the PALM–COEIN system, and discontinuation of its use is recommended (2). The diagnosis of AUB in reproductive-aged women is discussed elsewhere (3).