What Causes Dysfunctional Uterine Bleeding?

Medically reviewed by Holly Ernst, PA-C on May 8, 2018Written by April Kahn

Dysfunctional uterine bleeding (DUB) is a condition that affects nearly every woman at some point in her life. Also called abnormal uterine bleeding (AUB), DUB is a condition that causes vaginal bleeding to occur outside of the regular menstrual... Read More

Dysfunctional uterine bleeding (DUB) is a condition that affects nearly every woman at some point in her life. Also called abnormal uterine bleeding (AUB), DUB is a condition that causes vaginal bleeding to occur outside of the regular menstrual cycle. Certain hormonal conditions and medications may also trigger DUB.

The main cause of dysfunctional uterine bleeding is an imbalance in the sex hormones. Girls experiencing puberty and women entering menopause can have imbalanced hormone levels for months or even years. This causes sporadic bleeding, heavy bleeding, and/or spotting. Spotting is bleeding that is lighter than a normal menstrual period. It often appears brown, pink, or light red.

The hormonal imbalances that cause DUB can also result from certain medical conditions or be side effects of medications.

Medical conditions

Medical conditions that often cause dysfunctional uterine bleeding are:

  • Polycystic ovary syndrome (PCOS). This is an endocrine disorder that causes a woman to produce an increased amount of sex hormones. This may lead to an imbalance in estrogen and progesterone, making the menstrual cycle irregular.
  • Endometriosis. This condition results when the uterine lining grows outside of the uterus, such as on the ovaries. Endometriosis often causes heavy bleeding during regular periods.
  • Uterine polyps. These small growths occur within the uterus. Although their cause is unknown, polyp growth is heavily influenced by the hormone estrogen. Small blood vessels in the polyps can cause DUB, including spotting between periods.
  • Uterine fibroids. Uterine fibroids are small growths that occur within the uterus, uterine lining, or uterine muscle. Like polyps, the causes of uterine fibroids are unknown. But estrogen seems to play a role in their growth.
  • Sexually transmitted diseases (STDs). STDs that cause inflammation, like gonorrhea and chlamydia, may lead to DUB. Bleeding caused by STDs usually occurs after sex, when the lesions are aggravated.

Medications

Certain medications can also cause dysfunctional uterine bleeding, including:

Recognizing the symptoms of DUB

The most common symptom of DUB is bleeding outside of your normal periods. It can also occur within your menstrual cycle. Suspicious bleeding patterns include:

  • heavy menstrual bleeding
  • bleeding that contains many clots or large clots
  • bleeding that lasts more than seven days
  • bleeding that occurs less than 21 days from the last cycle
  • spotting
  • bleeding between periods

Other common symptoms that can occur with DUB are:

  • breast tenderness
  • bloating
  • pelvic pain or pressure

If you experience any of the following severe DUB symptoms, contact your doctor immediately:

How is DUB diagnosed?

To diagnose DUB, your doctor will ask questions about your medical history and the history of your cycle. These answers will help them determine your risks for certain reproductive disorders like PCOS and endometriosis. If you are taking any medication, including birth control, mention this to your doctor, as such drugs cause abnormal bleeding.

Ultrasound

Your doctor may recommend an ultrasound to view your reproductive organs. This examination will reveal whether you have any abnormal growths such as polyps or fibroids. It can also help to rule out internal bleeding.

Blood tests

Blood tests are used to measure your hormone levels and your complete blood count. Your hormone levels can often give quick insight into the cause of your bleeding. If you’ve had heavy or prolonged bleeding, a complete blood count reveals whether your red blood cell count is too low. A low red blood cell count can indicate anemia.

Endometrial biopsy

If an abnormal growth is causing the bleeding, or your uterine lining is unusually thick, your doctor will take a sample of the uterine tissue for testing. If there are any abnormal cell changes in the lining, a biopsy will reveal it. Abnormal cells can indicate hormone imbalances or cancer, among other things.

Is DUB treatable?

There are many treatment options available for DUB. Sometimes, in cases of puberty especially, no action is taken, as the hormones usually correct themselves. The right treatment for you will depend on the underlying cause of the bleeding.

The most common and simple treatment option for dysfunctional uterine bleeding is combination oral contraceptives. Combination oral contraceptives contain synthetic estrogen and progesterone. These both work to control and regulate the menstrual cycle. Contraceptive methods including some IUDs and the implant can also be used as hormonal treatment. If you aren’t trying to conceive, your doctor may recommend using one of these as a treatment option.

If the bleeding is suddenly very heavy and lower-dose medications aren’t an option, intravenous estrogen can be administered until the bleeding subsides. This is normally followed by a course of oral progestin to balance the hormones.

If you’re trying to conceive and you don’t have heavy bleeding, your doctor may prescribe the ovulation-stimulating drug clomiphene, also called clomid. Stimulating ovulation can stop prolonged menstrual bleeding by resetting your menstrual cycle.

Heavy and prolonged bleeding accompanied by a thickened uterine lining can be treated with a procedure called dilation and curettage (D and C). This is an outpatient surgical procedure used to remove part of the uterine lining by scraping it away.

If your uterine cells are found to be abnormal, your doctor may order an additional biopsy after treatment. Depending on the results of the biopsy — if the cells are cancerous, for instance — a hysterectomy may be recommended. A hysterectomy is a complete removal of the uterus and is usually a last resort.

Can DUB cause complications?

Generally, DUB is a temporary condition. Once the sex hormones are regulated, abnormal bleeding usually subsides.

Anemia is one of the main complications of heavy bleeding. If you develop anemia due to significant blood loss, your physician may treat it with minerals and vitamin supplements. In rare cases where the bleeding has caused significant blood loss, you may need a blood transfusion.

Medically reviewed by Holly Ernst, PA-C on May 8, 2018Written by April Kahn

16 possible conditions

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This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Medically reviewed by Holly Ernst, PA-C on May 8, 2018Written by April Kahn
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