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Quick Facts



The Manual's Editorial Staff

Last full review/revision Jun 2021| Content last modified Jun 2021
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What is a fibroid?

A fibroid is a tumor in a woman's uterus (womb). The uterus is the organ where babies grow before they are born. Fibroids aren't cancer, but they can be painful and cause bleeding and other symptoms.

  • Fibroids need treatment only if they are causing symptoms—most fibroids don’t need treatment

  • Up to 7 in 10 women have one or more fibroids by age 45

  • Fibroids may be tiny or as big as a basketball

  • Doctors check for fibroids with a physical exam and ultrasound (a test using sound waves to create a moving picture of the inside of your body)

  • Fibroids are more common in women who are overweight

  • You may need surgery to get rid of symptoms like pain or to make childbirth possible

What causes fibroids?

Doctors don’t know what causes fibroids.

High levels of the female hormones estrogen and progesterone make fibroids grow. Fibroids tend to get bigger when these hormone levels rise during pregnancy. They tend to shrink when these hormone levels go down during menopause.

What are the symptoms of fibroids?

Many fibroids don’t cause any symptoms. Your symptoms may depend on:

  • The number of fibroids you have

  • Where they are in your uterus

  • The size (bigger fibroids are more likely to cause symptoms)

Symptoms of fibroids can include:

  • Heavier bleeding during your period or a longer period (abnormal vaginal bleeding)

  • Anemia (a low number of red blood cells) from heavy period bleeding

  • Pain, pressure, or a feeling of heaviness in your lower belly area

  • A constant or sudden need to urinate (pee)

  • Constipation (difficulty passing poop)

  • Difficulty urinating

  • Swollen belly area

Fibroids can also cause problems with pregnancy such as:

  • Problems getting pregnant

  • Miscarriage (when your pregnancy ends before 20 weeks, before your baby can survive outside your body)

  • Going into labor too early

  • Unusual position of baby in your uterus

  • Too much blood lost after birth (postpartum hemorrhage)

Fibroids can grow so big they can’t get enough blood. This makes them shrink and causes you pain.

How can doctors tell if I have fibroids?

Doctors will do a pelvic exam and may suggest other tests. During a pelvic exam, your doctor presses on your belly to feel the size and shape of your uterus and ovaries. They also use tools to look inside your vagina and cervix (lower part of your uterus) to check for any problems.

To know for sure if you have fibroids, doctors may do other tests including:

  • Ultrasound using a wand placed inside your vagina (transvaginal ultrasound)

  • Ultrasound done after a doctor injects a fluid into your uterus to see the inside

  • MRI—an imaging test that uses a strong magnetic field to create a detailed picture of the inside of your body

  • Biopsy of the lining of your uterus

In a biopsy, the doctor removes a small amount of tissue from the lining of your uterus. The tissue is examined under a microscope to be sure you don't have a more serious problem, like uterine cancer.

How do doctors treat fibroids?

You won’t need treatment unless your symptoms bother you or are preventing you from getting pregnant. If your fibroids get large or start causing severe symptoms, treatment can include:

  • Medicines to shrink the fibroids and lessen bleeding

  • Sometimes, surgery to remove your fibroids or your uterus

  • Sometimes, procedures to destroy your fibroids and ease your symptoms

Procedures that can destroy fibroids include freezing them or using heat. Ultrasound or MRI may be used during the procedure to help your doctor see the fibroids.

Your fibroids may shrink on their own after menopause.

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