Abnormal uterine bleeding

If you experience heavy menstrual bleeding or bleeding in between periods, you may have a symptom called abnormal uterine bleeding (AUB).

Abnormal uterine bleeding refers to any irregularities in the menstrual cycle. You may experience irregularities in terms of frequency, duration, regularity or menstrual flow outside of pregnancy.

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Causes of abnormal uterine bleeding

Abnormal uterine bleeding is often linked with some kind of estrogen or progesterone hormone imbalance, hormone changes, uterine lining abnormalities, uterine growths or clotting problems. The most common causes of dysfunctional uterine bleeding are described by the acronym PALM-COEIN, which includes:

P: Polyps. Uterine polyps (endometrial polyps) are noncancerous growths in the lining of the uterus (endometrium). An endometrial polyp can often cause intermenstrual bleeding.

A: Adenomyosis. This is the presence of endometrial tissue in the myometrium, the muscular outer layer of the uterus. Adenomyosis often causes menstrual pain, as well as prolonged or heavy menstrual bleeding and sometimes an enlarged uterus.

L: Leiomyoma (fibroids). Fibroids are benign tumors that form in the muscular outer layer of the uterus. Likelihood of developing a uterine fibroid increases with age, and fibroids can be found in 80% of menstruating individuals. Fibroids are often accompanied with prolonged, excessive bleeding and pelvic pain.

M: Malignancy and hyperplasia. Dysfunctional uterine bleeding is a common symptom of endometrial cancer, which increases in likelihood with age. Unopposed estrogen exposure can make the uterus likely to develop malignant cancer cells, and creates variations in your menstrual bleeding.

C: Coagulopathy. Coagulopathy refers to any bleeding disorder, which affects about 20% of people with heavy menstrual bleeding.

O: Ovulatory dysfunction. Endocrine disorders can cause a dysfunctional ovulation, meaning that you may experience infrequent ovulation, or may not ovulate at all. Dysfunctional ovulation can cause a heavy, irregular or prolonged menstrual period. This often happens in people diagnosed with polycystic ovary syndrome.

E: Endometrial. Any endometrial dysfunction caused by inflammation or infection can cause abnormal uterine bleeding. This can also happen if the uterine lining grows too thick (endometrial hyperplasia).

I: Iatrogenic. Certain medical treatments can cause iatrogenic abnormal uterine bleeding (breakthrough bleeding), including hormonal contraception such as the birth control pill or hormonal IUD, hormone therapy, anticoagulants, cancer medication (Tamoxifen) or dopamine antagonists.

N. Not classified. Sometimes rare disorders or postoperative complications can lead to spotting or irregular uterine bleeding, including arterial malformations of cesarean scar defects.

What are the symptoms of abnormal uterine bleeding?

If you experience one or more of the following symptoms, you may have AUB:

  • Your period lasts longer than 7 days.
  • You get your period earlier than every 21 days apart, or later than 35 days apart.
  • You experience heavier bleeding than normal (menorrhagia).
  • You pass blood clots or soak through hygiene products like pads every hour for more than 2 hours.

If you experience these symptoms, please visit your provider for a proper diagnosis and to get the treatment you need.

How abnormal uterine bleeding is diagnosed

To diagnose abnormal uterine bleeding, your doctor will start by having you take a pregnancy test. This is to rule out the possibility that you actually have vaginal bleeding from an ectopic pregnancy or a miscarriage. If your abnormal vaginal bleeding is from a pregnancy complication, your doctor will refer you for immediate medical treatment, as an ectopic pregnancy may require surgery.

If your pregnancy test comes back negative, your doctor will then go through your overall health history and ask you questions regarding your menstrual history and how often you experience abnormal bleeding. They may ask you the following questions:

  • How old were you when you got your first period?
  • When was your last period?
  • Can you describe your frequency, duration, regularity and the amount of menstrual flow?
  • Do you experience bleeding in-between your periods or after sex?

Your doctor may then perform the following tests to help your doctor check for other causes of your symptoms.

Physical exam. Your doctor will take your vitals, check for signs of pallor (paleness) and feel your thyroid for enlargement or tenderness. Any thyroid abnormalities may indicate irregular hormone levels that may be causing irregular bleeding or menstruation.

Pelvic exam. Your doctor will feel your ovaries and uterus for swelling or inflammation. They may also use a device called a speculum to open your vagina and inspect your cervix, as well as your uterine cavity for any abnormalities such as polyps. They may also request a PAP smear or STI screening to collect samples of the cells in your cervix to detect cancer or other diseases.

Blood test. A sample of your blood will be collected to evaluate your complete blood count. This can help determine if you have any hormone imbalances or anemia, a condition where your blood doesn’t carry enough oxygen.

Ultrasound. Transvaginal ultrasonography may be used to show your uterus size, shape and any abnormalities including fibroids, ovarian problems or excess endometrial growth. This procedure uses sound waves to create an image of your organs. It should be used early on to examine the cause of your abnormal uterine bleeding.

Hysteroscopy. A thin, lighted tube is inserted into the vagina to examine the cervix and uterus, and can sometimes be used as an operation to remove fibroids, polyps or adhesions.

Endometrial biopsy. Your doctor may take a small tissue sample (endometrial biopsy) of your endometrium to test for endometrial cancer or hyperplasia. An endometrial biopsy test is considered first for people experiencing abnormal bleeding that are over the age of 45 or for people with conditions such as polycystic ovary syndrome.

Treatments for abnormal uterine bleeding

If you have abnormal uterine bleeding, let your doctor know and they will help you find ways to treat it. Your doctor will determine the best course of action based on your health, any pre-existing conditions and desire for biological children. The treatments may be designed to return your menstrual cycle to normal, to stop periods altogether or to reduce heavy menstrual bleeding.


Hormone therapy. Taking a daily birth control pill with estrogen and progestin may help control your menstrual cycle and reduce cramping or bleeding, while also preventing pregnancy.

Nonsteroidal anti-inflammatory drugs (NSAIDs). Taking regular doses of pain medications such as Ibuprofen can help relieve menstrual pain and heavy bleeding associated with menorrhagia.

Progestin IUD. Having a progestin IUD inserted can help control your menstrual cycle, prevent pregnancy and ease menorrhagia symptoms.

Tranexamic acid. This medication helps slow the breakdown of blood clots, preventing excessive bleeding. It is usually recommended for menstruating teenagers, or to treat acute AUB when the bleeding is too severe.

Surgical treatment

Endometrial ablation. An endometrial ablation procedure is also used when other treatments do not work to treat uterine fibroids. This procedure uses a laser, heat, electricity or freezing to destroy (ablate) the uterine lining. However, endometrial ablation is not recommended for those who wish to have children in the future.

Hysterectomy. This surgery involves removing the uterus and sometimes the fallopian tubes and/or ovaries. It is invasive and requires a hospital stay and will mean you cannot get pregnant in the future. This procedure is recommended for endometrial cancer, adenomyosis and severe uterine fibroids, often as a last resort for when hormone treatments fail to control menorrhagia. After a hysterectomy if your ovaries have also been removed, you will have to take estrogen or else you will start menopause right away.

Myomectomy. If you have uterine fibroids, they can be surgically removed through this procedure without affecting your ability to have children.

Uterine artery embolization. This procedure is used when other treatments do not work, mostly for uterine fibroids or polyps. During the procedure, the fibroid's or polyp’s blood supply is cut off by putting tiny particles in the uterine arteries, causing the fibroids or polyps to shrink.

Lifestyle changes

For people who are obese or who have polycystic ovary syndrome, lifestyle changes such as eating a different diet and following an exercise regime may help reduce abnormal bleeding symptoms.

Watchful waiting

In some cases, your doctor may recommend a wait-and-see approach to determine if your irregular vaginal bleeding can go away on its own or get better over time. This is usually recommended for teenagers or people nearing menopause, as they are going through hormone changes that will level out over time.

Can abnormal uterine bleeding cause any complications?

Don’t ignore abnormal uterine bleeding

If you experience abnormal uterine bleeding for more than 6 months, it is considered chronic abnormal uterine bleeding, which can lead to many complications. These include anemia, infertility or endometrial cancer.

If you have acute abnormal uterine bleeding (severe uterine bleeding with excessive blood loss), you may be at risk of severe anemia, shock, hypotension or death if you do not get immediate care.


MedlinePlus: National Library of Medicine. Abnormal uterine bleeding (https://medlineplus.gov/ency/article/000903.htm)

National Center for Biotechnology Information (NCBI): National Library of Medicine. Abnormal Uterine Bleeding (https://www.ncbi.nlm.nih.gov/books/NBK532913/)