Uterine fibroids, or leiomyomas, are tumors or growths made of smooth muscle cells, fibroblasts, and other material that grow in or on the wall of the uterus or womb. They are the most common non-cancerous tumors in women of childbearing age.
Uterine fibroids can cause pain and abnormal bleeding from the uterus. Sometimes, fibroids can make it difficult for a woman to get pregnant or maintain a pregnancy.
Currently, the only cure for fibroids is hysterectomy (pronounced hiss-tur-EK-toh-mee), or removal of the uterus, although fibroids can be treated with other methods.
NICHD scientists are exploring the causes of and treatments for fibroids—including non-hormonal treatments and solutions that preserve a woman’s fertility—and are seeking ways to prevent fibroids from occurring at all.
About Uterine Fibroids
Uterine fibroids are growths made of smooth muscle cells, fibroblasts, and other material that grow in or on the wall of the uterus.
Fibroids may grow as a single tumor or in clusters. In many cases, a single uterus contains many fibroids.
Health care providers categorize fibroids based on where they grow:
- Submucosal (pronounced sub-myoo-KOH-sul) fibroids grow just underneath the uterine lining and into the endometrial cavity.
- Intramural (pronounced in-tra-MYUR-ul) fibroids grow in between the muscles of the uterus.
- Subserosal (pronounced sub-sur-OH-sul) fibroids grow on the outside of the uterus.
Some fibroids grow on stalks that grow out from the surface of the uterus or into the uterine cavity. These are called pedunculated (pronounced ped-UN-kyoo-lay-ted) fibroids.
What are the symptoms of uterine fibroids?
Many women have no symptoms of fibroids. However, uterine fibroids can cause uncomfortable or sometimes painful symptoms, such as:
- Heavy bleeding or painful periods
- Anemia (when you don’t have enough red blood cells)
- Bleeding between periods
- Feeling “full” in the lower abdomen (belly)—this is sometimes called pelvic pressure
- Frequent urination (caused by a fibroid pressing on the bladder)
- Pain during sex
- Lower back pain
- Reproductive problems, such as infertility, multiple miscarriages, and early onset of labor during pregnancy
- Obstetrical problems, such as increased likelihood of cesarean section
What are the risk factors for uterine fibroids?
Fibroids usually grow in women of childbearing age, and research suggests that they may shrink after menopause. However, research also shows that they are more likely to shrink in postmenopausal white women than in postmenopausal black women. For African American women, fibroids typically develop at a younger age, grow larger, and cause more severe symptoms.1
- Age (older women are at higher risk than younger women)
- African American race
- Family history of uterine fibroids
- High blood pressure
- No history of pregnancy
- Vitamin D deficiency
- Food additive consumption
- Use of soybean milk
- Pregnancy (the risk decreases with an increasing number of pregnancies)
- Long-term use of oral or injectable contraceptives
What causes uterine fibroids?
We don’t know what causes uterine fibroids. Evidence suggests that multiple factors play a role in their growth.
Although exact causes are unknown, research evidence suggests that any or all of these factors might play a role in the growth of uterine fibroids:1
- Genetics (e.g., genetic mutations in the MED12, HMGA2, COL4A5/COL4A6, or FH genes)
- Estrogen and progesterone
- Growth hormones
- Micronutrients, such as iron, that the body needs only small amounts of in the blood.2 For instance, a deficiency of vitamin D may be associated with uterine fibroids.3
- Major stresses4,5
It is likely that fibroids are caused by many factors interacting with one another. Once we know the cause or causes of fibroids, our efforts to find a cure or even prevent fibroids could move ahead more quickly.
How are uterine fibroids diagnosed?
Unless a woman has symptoms, it’s likely she does not know she has uterine fibroids.
In some cases, though, health care providers find fibroids during a routine gynecological exam. During this exam, the health care provider checks the size of your uterus by putting two fingers of one hand into the vagina while using the other hand to press lightly on your abdomen. If you have fibroids, your uterus may feel larger than normal, or it may feel irregularly shaped.
The size of the fibroids does not seem to be related to the severity of symptoms, so even small fibroids may cause considerable symptoms and heavy periods. If you have symptoms but your health care provider cannot feel any fibroids during a manual examination, he or she may use one or more types of imaging technology—machines that create a picture of the inside of your body—to diagnose uterine fibroids.
Some common types of imaging technology are:
- Ultrasound, which uses sound waves to form the picture
- Saline infusion sonography, which uses an injection of salt solution into the uterus to help create the ultrasound image
- Magnetic resonance imaging (MRI), which uses magnets and radio waves to create the picture
- X-rays, which use a form of electromagnetic radiation to “see” into the body
- Computed tomography (CT) or computer-assisted tomography (also called a CAT scan), which scans the body with X-rays from many angles to create a more complete picture
What are the treatments for uterine fibroids?
Treatments for fibroids include the following:
This page also includes information about emotional support for living with fibroids.
Your health care provider will consider several factors before recommending a treatment for your fibroids, including:
- Your age
- Your general health
- How severe your symptoms are
- Where your fibroids are located
- The type and size of the fibroids
- Whether you are pregnant now or want to get pregnant in the future
If you have uterine fibroids but have no symptoms or problems, you may not need treatment. You can ask your health care provider to continue to check the fibroids at your routine gynecological exams to see whether they have grown. If you are close to menopause, your health care provider may find that your fibroids are shrinking, which is common during and after menopause.
Medication-Related Treatments for Fibroids
Depending on your symptoms, your health care provider may suggest medical treatments that can reduce the symptoms of fibroids or stop their growth. Certain medical treatments to reduce fibroid size and blood loss may be used in combination with other treatments.
- Pain medicine. Over-the-counter or prescription medicine is often used for mild or occasional pain from fibroids.
- Birth control pills or other types of hormonal birth control. These medicines help control heavy bleeding and painful periods. However, this therapy can sometimes cause fibroids to grow larger.
- Progestin-releasing intrauterine device (IUD). The hormonal IUD, also called intrauterine contraception (IUC), reduces heavy and painful bleeding but does not treat the fibroids themselves. It is not recommended for women who have very large fibroids, which can block the uterine cavity.
- Gonadotropin-releasing hormone agonists (GnRHa). These medicines block the body from making the hormones that cause women to ovulate and have their periods. The medicines also reduce the size of fibroids. Because this treatment can cause side effects that mimic the symptoms of menopause (such as hot flashes, night sweats, and vaginal dryness) and bone loss (which weakens the bones), it is not meant for long-term use. Most of the time, these medicines are used for a short time to reduce the size of fibroids before surgery or to treat anemia. If you need to take this treatment for a long time, the doctor may prescribe different medicine to put back the hormones that were blocked.
- Antihormonal agents or hormone modulators (such as selective progesterone receptor modulators). These drugs, which include ulipristal acetate, mifepristone, and letrozole, can slow or stop the growth of fibroids, reduce bleeding, and improve symptoms.
Medical treatments may give only temporary relief from the symptoms of fibroids. Once you stop the treatment, fibroids can grow back and symptoms can return.
Medicines are generally safe, but they can have side effects, some of which may be serious. Be sure to talk to your health care provider about the possible side effects of any medical treatment you consider.
Hysterectomy is the only sure way to cure uterine fibroids completely. Health care providers may recommend this option if you are near or past menopause and you have large fibroids or very heavy bleeding.
During a hysterectomy, the whole uterus or just part of it is removed.
- Abdominal hysterectomy. The surgeon removes the uterus through a cut in the abdomen. This incision may be similar to what is done during a cesarean section. This type of hysterectomy requires a longer hospital stay and longer recovery time than others.1 Removal of the ovaries is not required for treatment of fibroid symptoms. Similarly, some women may desire to preserve the cervix if there is no history of abnormal Pap smears.
- Vaginal hysterectomy. Instead of making a cut into the abdomen, the surgeon removes the uterus through the vagina. This method is less invasive than an abdominal hysterectomy, so recovery time is usually shorter (3 to 4 weeks). Vaginal hysterectomy may not be an option if your fibroids are very large.
- Laparoscopic hysterectomy. Minimally invasive approaches include laparoscopic hysterectomy, laparoscopy-assisted vaginal hysterectomy, and robotic-assisted laparoscopic hysterectomy. Not all cases of uterine fibroids can be treated with such approaches, but these methods may result in reduced postoperative recovery time.
- Robotic hysterectomy. Robotic hysterectomy is becoming more common. The surgeon sits at a console near the patient and guides a robotic arm to perform laparoscopic surgery. Like laparoscopic myomectomies, this technique requires only small incisions in the uterus and abdomen. As a result, recovery can be shorter (3 to 4 weeks) than with more invasive procedures. More research is needed to understand how (and how well) these procedures work and to compare the outcomes with those of other established surgical treatments.
If you have not gone through menopause and are considering a hysterectomy for your fibroids, talk to your health care provider about keeping your ovaries. The ovaries make hormones that help maintain bone density and sexual health even if the uterus is removed. If your body can continue to make these hormones on its own, you might not need hormone replacement after the hysterectomy.
Having a hysterectomy means that you will no longer be able to get pregnant.3 This process cannot be reversed, so be certain about your choice before having the surgery.
Other Treatments for Fibroids
Uterine fibroids can be treated with radiological and other methods. These can include endometrial ablation, uterine artery embolization, magnetic resonance imaging–guided focused ultrasound, and myomectomy.
These treatments are minimally invasive and typically involve a short hospital stay or can be done as an outpatient procedure. Before undergoing any treatment for uterine fibroids, you should discuss your options with your health care provider.
Emotional Support for Living with Fibroids
Emotional support may be just as important as medical treatment for dealing with the chronic symptoms and potential reproductive problems associated with fibroids. Many women find that joining a support group and talking to other women who have fibroids helps them come to terms with their condition.
Hospitals and health clinics may offer support groups for women and families affected by fibroids. Your health care provider may be able to refer you to a support group. You may also find it helpful to work with a “professional listener,” such as a social worker, a psychologist, a psychiatrist, or another mental health professional. The Resources page of this topic offers links to organizations that provide information and support for women with uterine fibroids.