Dysfunctional uterine bleeding (DUB) involves changes to menstruation patterns, such as changes in regularity, duration, or flow. DUB can happen for many different reasons.

Dysfunctional uterine bleeding (DUB) is bleeding that occurs outside typical menstrual patterns. Some doctors may refer to DUB as menstrual irregularities or abnormal uterine bleeding.

While estimates vary, data suggests that about one-third of women experience DUB at some point in their lives. It can happen at any age. However, abnormal bleeding is more likely when a person begins to menstruate and during perimenopause.

In most cases, DUB is not a symptom of a serious underlying condition. However, in some cases, it can cause substantial blood loss.

This article outlines the causes, symptoms, diagnosis, complications, treatment, and prevention of DUB.

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Some people have heavier periods than others, and menstrual flow may change throughout a person’s life. Menstrual irregularities are not always the result of an underlying condition.

However, some medical conditions and medications can cause abnormal uterine bleeding.

Medical conditions

DUB may also result from:


Some medications can also cause DUB, such as:

  • hormonal birth control
  • blood thinners
  • aspirin

Blood thinners are medications that limit the blood’s capacity to clot. Taking them can lead to heavier or prolonged bleeding during menstruation.

Hormonal birth control can also impact bleeding frequency. Some people may even experience breakthrough bleeding (bleeding that occurs outside the typical menstruation period) while taking hormonal birth control.

Additionally, abnormal uterine bleeding is a rare side effect of glucocorticoids, a class of corticosteroid medications that help with inflammation.

DUB is a symptom, not a condition in and of itself. It refers to a change in menstruation, which may include:

  • spotting or bleeding outside of menstruation
  • heavy bleeding during menstruation
  • prolonged bleeding during menstruation
  • irregular menstrual cycles
  • lack of menstruation
  • bleeding after menopause

Depending on the underlying cause of DUB, people may experience other symptoms in addition to bleeding, such as:

  • pain
  • vaginal discharge
  • weight loss
  • bowel or bladder problems

People with DUB might also have anemia, bleeding disorders, or endocrine disorders.

To determine the underlying cause of DUB, doctors will ask about typical menstruation patterns.

Because there are many possible causes for abnormal uterine bleeding, testing can help narrow down the diagnosis. A doctor may order one or more of the following tests:

  • urine pregnancy test
  • complete blood count (CBC)
  • coagulation panel
  • thyroid function tests
  • MRI scans
  • transvaginal and pelvic ultrasound
  • hysteroscopy
  • endometrial tissue biopsy

Possible treatment options for abnormal uterine bleeding include:

  • Hormonal birth control: Birth control options containing estrogen and progestin may help with heavy, irregular periods, including those due to fibroids, ovulation, and polycystic ovary syndrome (PCOS).
  • Hormone therapy: This may be an option for folks experiencing abnormal bleeding during perimenopause. However, hormone therapy comes with risks. It is important to discuss these with a healthcare professional.
  • Tranexamic acid: This prescription drug can help with chronic heavy menstrual bleeding.
  • Nonsteroidal anti-inflammatories (NSAIDs): These may help with painful, heavy periods.
  • Surgery: Different types of surgery may help stop bleeding when medications do not work.

Doctors may also recommend stopping or changing birth control medications if they believe they are causing abnormal bleeding.

Medications that help the blood clot may prevent heavy periods in people with a bleeding disorder.

Because DUB is often a symptom of an underlying condition, doctors will focus on treating the underlying cause of the bleeding. Treatment may vary depending on the underlying cause. For example, if cancer is causing the bleeding, a doctor may recommend surgery or radiation.

Complications of DUB depend largely on the underlying cause. However, chronic bleeding may cause:

  • infertility
  • anemia
  • low blood pressure

In rare cases, untreated sudden abnormal uterine bleeding can cause severe blood loss, which may be life threatening.

People who experience abnormal uterine bleeding may want to consider consulting a medical professional.

While most causes for abnormal bleeding are not typically a cause for concern, early diagnosis and treatment for serious underlying causes can help prevent complications.

Sudden, heavy uterine bleeding requires immediate medical attention.

DUB refers to a change in typical menstruation patterns. It may involve changes in menstrual regularity, frequency, duration, and in the amount of blood lost. Medical conditions and medications are possible causes of DUB.

In some cases, untreated DUB may lead to anemia or infertility.