Dysfunctional uterine bleeding (DUB) happens when an individual has vaginal bleeding that is not part of their regular menstrual cycle. A result of an imbalance in sex hormones, many conditions may cause DUB. There are treatment options.

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 spotting.

Spotting is bleeding that’s 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 that often cause dysfunctional uterine bleeding are:

  • Polycystic ovary syndrome (PCOS). This is an endocrine disorder that causes a woman to produce an imbalanced 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 can cause 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.
  • Pregnancy. AUB can be an early symptom of pregnancy.

Certain medications can also cause dysfunctional uterine bleeding, including:

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 7 days
  • bleeding that occurs less than 21 days from the last cycle
  • bleeding that occurs later than 35 days from the last cycle
  • spotting
  • bleeding between periods

Other common symptoms that can occur with DUB are:

  • bloating
  • pelvic pain or pressure

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

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’re taking any medication, including birth control, mention this to your doctor, as such drugs can cause abnormal bleeding.


Your doctor may recommend an ultrasound to view your reproductive organs. This examination can help 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 may take a sample of the uterine tissue for testing.

If there are any abnormal cell changes in the lining, a biopsy may reveal it. Abnormal cells can indicate hormone imbalances or cancer, among other things.

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 progestin IUDs and the progestin implant can also be used as hormonal treatment.

If you’re not 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 may be 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.

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.

Dysfunctional uterine bleeding is very common and is rarely cause for concern.

However, if you experience other symptoms in addition to irregular bleeding, or if you feel concerned about your symptoms, talk with your doctor.