NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health. [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.

Cover of [Internet].

Show details

Uterine fibroids: Overview

Created: ; Last Update: November 16, 2017; Next update: 2020.


Many women have benign (non-cancerous) growths known as fibroids in or on their womb (uterus). Most fibroids are small and don't cause any problems. They are usually discovered by chance. Depending on where fibroids are located, they may cause period pain, heavy menstrual bleeding or other symptoms.

There are different ways to treat fibroids. The most suitable treatment will greatly depend on a woman’s individual circumstances – such as whether she would still like to have children.

Fibroids are made up of muscle cells and connective tissue. Their size, shape and location vary. Fibroids are mainly categorized based on where they are:

  • Directly under the lining of the womb (submucosal fibroids)
  • In the wall of the womb (intramural fibroids)
  • On the outer wall of the womb (subserosal fibroids)
  • In the cervix (cervical fibroids)
  • In the connective tissue next to the womb (intraligamentary fibroids)
Illustration: Different types of fibroids

Fibroids: Different types


Many women who have fibroids don't notice that they have them. Some may just have one, while others have several. Fibroids most commonly cause symptoms in women between the ages of 30 and 50. Typical symptoms include the following:

  • Severe or prolonged menstrual bleeding
  • Severe, cramp-like period pain
  • Diffuse pain and tension in the abdomen

Fibroids usually cause symptoms if they affect the function of the womb, for example during menstrual bleeding. Fibroids that grow just under the lining of the womb are particularly likely to cause heavy menstrual bleeding. Regular heavy periods can lead to anemia. Women who have anemia often look pale and feel tired.

Larger fibroids sometimes push against neighboring organs like the bladder or bowel. This can cause an increased urge to urinate or digestion problems (constipation, pain). Back pain or trouble urinating (urinary retention) are possible too, but rare.

“Pedunculated” fibroids may cause sudden and severe pain. These fibroids can grow on the inner and outer wall of the womb. They are connected to the womb by a thin, stem-like structure. Abrupt movements can cause pedunculated fibroids to rotate on these stems. This interrupts the blood flow to the fibroid, which can be extremely painful.

Causes and risk factors

It is not known exactly why fibroids develop. It is thought that genetic factors play a role. The female sex hormones estrogen and progesterone have a big influence, but to different degrees. Fibroids can't grow without these natural hormones produced in a woman’s body, which is why symptoms often stop once women enter menopause. Artificial hormones, such as those used in birth control pills, tend to slow fibroid growth.

Fibroids are more common in the following groups of women:

  • Black women: Fibroids are two to three times more common in black women – but the exact reason is not known.
  • Women who have never been pregnant.
  • Women whose mother or sister has had fibroids.
  • Women who are very overweight. But it's not clear whether the extra weight itself is the cause.

Fibroids are less common in these women:

  • Women who have had several children.
  • Women who have used birth control pills for several years.

It's not clear whether there's a link between your diet and the development of fibroids.


Experts estimate that about 40 to 80% of all women have fibroids. Many of the fibroids are very small, and most women never notice that they have them. Fibroids only sometimes cause symptoms, but it's difficult to say exactly how often, and how likely they are to do so.

It's also hard to predict how a fibroid will continue to develop: Fibroids grow to different sizes and at different speeds. Some fibroids and their associated symptoms hardly change despite not having treatment. Other fibroids grow bigger, and the symptoms get worse over time. Symptoms may also gradually go away on their own.

Fibroids usually become smaller after a woman has reached menopause, and then the symptoms nearly always disappear as well. Having hormone therapy for menopause symptoms may prevent fibroids from shrinking in some cases. Then the fibroid symptoms don't go away either.


Fibroids usually don't have any other negative effects aside from the symptoms already described and the related problems. But many women worry that fibroids may affect their fertility. This is only true of certain types of fibroids. Experts estimate that only 1 to 2% of infertility cases are caused by fibroids. Most women who have fibroids can still become pregnant.

Fibroids that grow just under the lining of the womb are particularly likely to disrupt the function of the womb – for example by preventing fertilized egg cells from attaching. Fibroids that grow on the outside of the womb probably don't affect fertility. It is not known whether fibroids in the wall of the womb affect fertility.

Fibroids also don't usually increase the risk of complications during pregnancy. It is believed that only fibroids in the wall of the womb and under the lining of the womb may increase the risk of miscarriage. Fibroids in general probably hardly affect the risk of a baby being born too soon. A fibroid that is very low down in the womb may stop the baby’s head from entering the lower pelvis during birth, making a Cesarean section necessary.

Some women worry that fibroids might turn cancerous, but this fear is unjustified. Fibroids are not cancerous. People used to think that fibroids could develop into cancerous tumors in connective tissue (sarcoma) in extremely rare cases, but there is no scientific proof to support this.

Fibroids can cause urinary retention, but that is very rare. This happens if large fibroids press against a ureter. If a ureter becomes completely pinched off, surgery is needed quickly to prevent urine from flowing back, which may permanently damage the kidney on the affected side.


Fibroids that don't cause any symptoms are often first detected in routine ultrasound examinations during a visit to the gynecologist or while trying to diagnose a different illness.

Fibroids are also often diagnosed when women see a doctor because of problems like period pain or heavy menstrual bleeding.

Larger fibroids may be discovered by feeling during a gynecological examination. Then an ultrasound examination from inside the vagina can provide more information about the number, shape, position and size of the fibroids. Depending on the results, further examinations may be needed, such as magnetic resonance imaging (MRI).


Fibroids usually only need to be treated if they are causing fertility problems or could cause problems during pregnancy. The choice of treatment will mainly depend on whether a woman would still like to have children – and how she sees the advantages and disadvantages of the various treatments. The severity of the symptoms and the size and position of the fibroids may also determine which treatments are an option.

There is no rush to make a treatment decision. Fibroids usually grow very slowly. So you can take your time to read up on all of the pros and cons of the different treatments. Sometimes it is also a good idea to get several opinions from different doctors.

The treatment goals may include the following:

  • Reduce menstrual bleeding
  • Relieve pain, cramps and tension
  • Help with difficulties emptying the bladder and digestion
  • Preserve or improve fertility

The treatment options include:

  • Hormone therapies: The main hormone therapies are hormonal contraceptives to reduce heavy menstrual bleeding, and hormones that prevent the production of estrogens (GnRH analogues).
  • Surgical removal of the fibroid or the entire womb.
  • Closing off the blood vessels that supply the fibroid with blood (uterine fibroid embolization). The aim is to shrink the fibroids.
  • Other procedures like focused ultrasound surgery (FUS). This is a relatively new procedure, and its advantages and disadvantages have not yet been fully studied. FUS uses high-intensity ultrasound waves to heat and destroy the fibroid.
  • Other treatments like painkillers, herbal remedies or acupuncture.

NSAID (non-steroidal anti-inflammatory drug) painkillers like ibuprofen or diclofenac have been proven to relieve period pain. But there are no studies that have specifically looked into the effects of NSAIDs in women with fibroids. This is also true for acupuncture. Some herbal remedies have been studied more than others, but there's currently no evidence that they are effective in treating fibroids.

Everyday life

Severe period pain and heavy menstrual bleeding can be a real problem. Most women aren't aware that they might be caused by fibroids. If you have been diagnosed with fibroids, it's a good idea to get enough information to help you understand what they are and find the best way for you to deal with them. This is especially true if you would still like to have children.

It's important to manage the symptoms and keep them from affecting your life at home and at work too much. For instance, many women find heavy menstrual bleeding bothersome or embarrassing. They may even find it frightening. Severe pain can have a major impact on everyday life for a few days every month. But there are things you can do to make things easier. Many women learn how to better manage their symptoms over time. Understanding and support from their partner and friends and family can also make a real difference.

Further information

Some treatments and operations can only be carried out in a hospital. Read about how best to prepare for treatment in a hospital – for example, what hospital processes to expect, what documents to take along with you, and what you may have to pay for yourself.


© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK279535


Informed Health Links

Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...