Abnormal Uterine Bleeding Mechanisms

AUB names a bleeding pattern; it does not identify its cause. For a non-pregnant patient in the reproductive years, describe the pattern using FIGO’s four dimensions: how often bleeding recurs, how long it lasts, how predictable it is, and how much it affects the patient. A cycle recurring about every 24–38 days and bleeding lasting up to 8 days fall within the usual range; volume is judged by the patient’s experience and effect on life, not by an obligatory 80-mL collection. The cause is then organised with PALM–COEIN. PALM covers structural disease—polyp, adenomyosis, leiomyoma, and malignancy or hyperplasia. COEIN covers non-structural causes—coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not otherwise classified causes. The sequence matters: a patient can have anovulation and still develop hyperplasia, so “hormonal” bleeding is not a reason to skip risk-based assessment. Before that classification, rule out pregnancy and decide whether blood loss is impairing perfusion.