Emergency? If you are soaking through a pad or tampon every hour, feel faint or short of breath, or might be pregnant and are bleeding with pain, call 911 or go to the nearest emergency room. Know the warning signs
Book now

Abnormal Uterine Bleeding

A short video introduction to abnormal uterine bleeding: what it is, why it happens, and when to get it checked.

By Dr. David Howard, MD, PhD, FACOGPublished March 1, 2024Updated September 2026Overview

Key points

Abnormal uterine bleeding (AUB) is bleeding from the uterus that is unusual in how heavy it is, how long it lasts, how often it comes, or how regular it is. It is one of the most common reasons people see a gynecologist.

Doctors sort its causes with a system called PALM-COEIN. The PALM causes are structural, found on imaging or in tissue: polyps, adenomyosis, leiomyomas (fibroids), and malignancy or hyperplasia. The COEIN causes are not structural: coagulopathy (bleeding disorders), ovulatory dysfunction, endometrial causes, iatrogenic causes (from medicines or devices), and causes not yet classified.

Most causes are treatable. The first steps are usually a pregnancy test, blood work, and a pelvic ultrasound. Explore each cause, or book a visit to start your evaluation.

Sources

  1. Munro MG, Critchley HOD, Fraser IS; FIGO Menstrual Disorders Committee. The two FIGO systems for normal and abnormal uterine bleeding symptoms and classification of causes of abnormal uterine bleeding in the reproductive years: 2018 revisions. Int J Gynaecol Obstet. 2018;143(3):393–408.
  2. American College of Obstetricians and Gynecologists. Practice Bulletin No. 128: Diagnosis of abnormal uterine bleeding in reproductive-aged women. Obstet Gynecol. 2012;120(1):197–206 (reaffirmed).

Related