Overview and Types of Abnormal Uterine Bleeding

If you are experiencing bleeding that is different from your regular period, you may be very worried. Once you have become used to the pattern of your regular cycle, any bleeding that happens outside of your normal period can be unsettling.

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Irregular bleeding used to be called dysfunctional uterine bleeding. But with new diagnostic terminology in place, the experts recommend that the term dysfunctional uterine bleeding is changed to abnormal uterine bleeding.

What Is Abnormal Uterine Bleeding?

Abnormal uterine bleeding is a menstrual cycle disorder. Any bleeding that is outside of your regular cyclic menstruation is considered abnormal uterine bleeding. Any change in the amount or duration of your period is also considered abnormal uterine bleeding. Abnormal uterine bleeding can range from a random day of light spotting to 10 days of heavy bleeding replacing your normal menstrual flow.

During your reproductive years, it is likely that you will experience some type of abnormal uterine bleeding at least once. Abnormal uterine bleeding that occurs only once usually does not indicate any significant underlying problem. If you have 3 consecutive months of abnormal bleeding it is more likely that you have an underlying problem causing the bleeding.

If you are just starting to menstruate or if you are in the last few years of your regular menstrual cycles or perimenopausal, you are at an increased risk of experiencing abnormal uterine bleeding.

Diagnosing AUB

The diagnosis of abnormal uterine bleeding is based on your complaints of changes to your menstruation. There are four main variables that describe menstruation:

  • How much you bleed?
  • How many days do you bleed?
  • How often you bleed?
  • How regular are the intervals between your periods?

What you report as changes in the amount, duration, frequency, and regularity of your periods is the information used by your healthcare provider to make the diagnosis of abnormal uterine bleeding.


To diagnose the cause of your abnormal uterine bleeding, your healthcare provider will give you a pelvic exam and exam of the cervix and may order one of the following tests:

  • Blood tests—to check hormone levels, thyroid, and rule out blood diseases
  • Ultrasound exam—to make a picture of the pelvic organs.
  • Hysteroscopy—to see the inside of the uterus.
  • Endometrial biopsy—to examine the endometrium under a microscope
  • Sonohysterography—to make images of the inside of the uterus
  • Magnetic resonance imaging (MRI)—to create images of the internal organs
  • Computed tomography (CT)—to show a cross-section of internal organs and structures


Up until recently, a diagnosis would be given based on the description of the bleeding alone. A new classification system has been introduced that uses the umbrella diagnosis of abnormal uterine bleeding or AUB.

Depending on the quality of the bleeding AUB it is then further defined as:

  • Abnormal uterine bleeding with heavy menstrual bleeding (AUB/HMB)
  • Abnormal uterine bleeding with bleeding between periods (AUB/IMB)

Outdated Terminology

These are some of the once-popular terms (now outdated terms), which the experts now recommend should be used only for research purposes. You may still see these terms used by your healthcare provider or in your internet searches.

  • Menorrhagia: This term is used to describe a period with a heavier flow than normal. By definition more than 80 ml of menstrual blood loss during your period.
  • Metrorrhagia: This term describes any bleeding that happens in between your regular periods.
  • Menometrorrhagia: This term describes a combination of heavy periods and bleeding between periods.
  • Dysfunctional uterine bleeding: This term was used much more commonly than abnormal uterine bleeding as a diagnosis. The experts recommend that this term should no longer be used at all.

The following terms describe the frequency of your bleeding.

  • Polymenorrhea: This term describes a period that comes more frequently than every 21 days.
  • Oligomenorrhea: This term describes a period that comes at intervals greater than every 35 days. 


Once you undergo additional testing and evaluation your healthcare provider will be able to determine a cause of your bleeding and can further classify you as abnormal bleeding due to the following structural and nonstructural causes:

Structural causes (changes in your uterus):

  • Polyps (AUB-P)
  • Adenomyosis (AUB-A)
  • Leiomyoma (AUB-L)
  • Malignancy and hyperplasia (AUB-M)

Nonstructural causes: 

  • Coagulopathy (AUB-C)—abnormal bleeding due to an underlying bleeding condition
  • Ovulatory dysfunction (AUB-O)—abnormal bleeding because you are not ovulating regularly
  • Endometrial (AUB-E)—abnormal bleeding because of a problem with the lining of your uterus like an infection
  • Iatrogenic (AUB-I)—abnormal bleeding because of a medication you are taking
  • Not yet specified (AUB-N)—your healthcare provider can't find an underlying reason for your abnormal bleeding

Other causes:

  • Birth control methods (intrauterine device (IUD) or birth control pills)
  • Miscarriage or ectopic pregnancy

A Word From VeryWell

If you are experiencing abnormal uterine bleeding you should discuss your symptoms and your concerns with your healthcare provider as changes in your menstruation are often a sign of an underlying condition.

Abnormal uterine bleeding that is heavy and/or frequent can also cause you to become anemic. Anemia caused by chronic blood loss makes you tired and weak. With significant blood loss, you may experience shortness of breath and/or heart palpitations, fainting, or chest pain as your body tries to compensate for your anemia. This puts significant stress on your heart and can be very dangerous for you if you have ​underlying cardiovascular disease. 

Updated by Andrea Chisholm MD

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Munro MG, Critchley HO, Broder MS, Fraser IS. FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding in nongravid women of reproductive age. Int J Gynaecol Obstet. 2011;113(1):3-13. doi:10.1016/j.ijgo.2010.11.011

  2. Kaunitz A. Patient education: Abnormal uterine bleeding (beyond the basics). UpToDate.

  3. The American College of Obstetricians and Gynecologists. Abnormal uterine bleeding.

  4. American Congress of Obstetricians and Gynecologists. Practice bulletin no. 128: diagnosis of abnormal uterine bleeding in reproductive-aged women. Obstet Gynecol. 2012;120(1):197-206. doi:10.1097/AOG.0b013e318262e320

  5. The American College of Obstetricians and Gynecologists. Heavy menstrual bleeding.

By Tracee Cornforth
Tracee Cornforth is a freelance writer who covers menstruation, menstrual disorders, and other women's health issues.