PALM-COEIN classification system for abnormal uterine bleeding in nongravid reproductive-age women

Basic classification system. The basic system comprises four categories that are defined by visually objective structural criteria (PALM: polyp, adenomyosis, leiomyoma, and malignancy and hyperplasia), four that are unrelated to structural anomalies (COEI: coagulopathy, ovulatory dysfunction, endometrial, iatrogenic), and one reserved for entities that are not otherwise classified (N). The leiomyoma category (L) is subdivided into patients with at least one submucous myoma (L_SM) and those with myomas that do not impact the endometrial cavity (L_O). In the 2018 version, the words "submucosal" and "other" do not appear and the phrase "not yet classified" has been changed to "not otherwise classified."