Causes of abnormal uterine bleeding

Gynecologists sort the causes of abnormal bleeding with a system called PALM-COEIN, published by the International Federation of Gynecology and Obstetrics (FIGO). The first four letters are structural causes that can be seen on imaging or in tissue. The last five are not structural.

The system applies to people who are not pregnant and are in their reproductive years. It is also a useful map later in life. More than one cause is often present at the same time, and finding each one shapes treatment.

• Polyps AUB-POvergrowths of the uterine lining.
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• Adenomyosis AUB-ALining tissue growing into the uterine wall.
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• Fibroids (leiomyomas) AUB-LNon-cancerous muscle growths of the uterus.
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• Endometrial hyperplasia and cancer AUB-MPrecancer and cancer of the uterine lining.
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• Bleeding disorders AUB-CProblems with blood clotting, most often von Willebrand disease.
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• Ovulatory dysfunction AUB-OIrregular or absent ovulation, including PCOS and thyroid disease.
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• Endometrial causes AUB-EHeavy bleeding from the lining itself, with regular cycles.
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• Medication-related causes AUB-IBleeding caused by hormones, IUDs, blood thinners, and other medicines.
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• Other causes AUB-NLess common causes, such as a cesarean scar defect.
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