What Are Fibroids?
Uterine fibroids (also called myomas or leiomyomas) are benign (noncancerous) tumors of muscle tissue that can change the shape or size of the uterus and sometimes the cervix. They start in the smooth muscle cells inside the wall of the uterus (myometrium). Fibroids usually occur in the form of multiple tumors, although single fibroids are sometimes possible. Fibroids are noted in 20% of women in the reproductive years. Whether fibroids cause symptoms or require any type of treatment depends on their location and size in the uterus. Fibroids occur when a single muscle cell in the wall of the uterus multiplies to form a noncancerous tumor. The exact cause of uterine fibroids is unclear, but there is evidence that it may be a combination of genetic, hormonal, and environmental factors.
Fibroids are usually found in or around the body of the uterus, but they sometimes occur in the cervix. Fibroids within the uterus can be divided into three categories: subserous (located in the outer wall of the uterus); intramural (found in the muscular layers of the uterine wall); and submucous (protruding into the uterine cavity).
Can fibroids decrease fertility?
Uterine fibroids are common, and they are found in 5-10% of infertile women. Certain types of fibroids are known to decrease fertility. They include fibroids that are inside the uterine cavity and very large fibroids (>6 cm in diameter) that are located within the wall of the uterus. Because most women with fibroids will not be infertile, they and their partners should have a thorough evaluation to detect other problems that can decrease fertility. A fertility specialist can help determine if fibroids might be hampering their ability to conceive.
How do fibroids cause infertility?
There are several explanations for why uterine fibroids may reduce fertility.
- Changes in the position of the cervix (the vaginal opening to the womb) due to fibroids located above it may affect the number of sperm that can travel through the cervix.
- Changes in the shape of the uterus can interfere with sperm movement.
- Blockage of the fallopian tubes by the fibroids.
- Affecting the blood flow to the uterine cavity where the embryo would implant.
- Changes in the uterine muscle that prevents movement of the sperm or the embryo.
Uterine fibroids are common and can affect fertility in many ways. They can affect ovulation, fertilization and implantation. Treatment options vary, but treatment will help to address the gynecologic symptoms of fibroids and improve overall fertility. Our fertility experts will work to address your individual situation, as the proper management of uterine fibroids will depend upon the severity of your symptoms.
Find more information in the Fertility Library.
What are uterine fibroids?
Fibroids are firm, compact tumors made of smooth muscle cells and fibrous connective tissue. They develop in the uterus. Uterine fibroids are very common in women of reproductive age. Only a small number of these fibroids are large enough to be found by a healthcare provider during a physical exam. Fibroids are also known as uterine myomas, leiomyomas, or fibromas.
In most cases, the tumors are not cancer. These tumors are not linked to cancer and do not increase a woman's risk for uterine cancer. They may range in size, from the size of a pea to the size of a softball or small grapefruit.
What causes uterine fibroid tumors?
The cause of uterine fibroids is not known. But, it’s thought that each tumor develops from an abnormal muscle cell in the uterus. This cell multiplies rapidly because of the effect of estrogen.
Who is at risk for uterind fibroids?
Women who are nearing menopause are at the greatest risk for fibroids. This is because of their long exposure to high levels of estrogen. Women who are obese and of African-American heritage also seem to be at an increased risk. The reasons for this are not clearly understood.
Other risk factors:
- Diet high in red meat
- Family history of fibroids
- High blood pressure
What are the symptoms of uterine fibroids?
Some women who have fibroids have no symptoms, or have only mild symptoms. Other women have more severe, disruptive symptoms. The following are the most common symptoms for uterine fibroids. Symptoms of uterine fibroids may include:
- Heavy or prolonged periods
- Abnormal bleeding between periods
- Pelvic pain, caused as the tumor presses on pelvic organs
- Frequent urination
- Low back pain
- Pain during intercourse
- A firm mass, often located near the middle of the pelvis, which can be felt by your healthcare provider
How are uterine fibroids diagnosed?
Fibroids are most often found during a routine pelvic exam. Your health care provider may feel a firm, irregular pelvic mass during an abdominal exam. Other tests may include:
- X-ray. Electromagnetic energy used to produce images of bones and internal organs onto film.
- Transvaginal ultrasound. An ultrasound test using a small instrument, called a transducer, that is placed in the vagina.
- MRI. A non-invasive procedure that produces a two-dimensional view of an internal organ or structure.
- Hysterosalpingography. X-ray exam of the uterus and fallopian tubes that uses dye. It is often done to rule out tubal obstruction.
- Hysteroscopy. Visual exam of the canal of the cervix and the interior of the uterus using a viewing instrument (hysteroscope) inserted through the vagina.
- Endometrial biopsy. A procedure in which a sample of tissue is taken through a tube inserted into the uterus.
- Blood test. This is to check for iron-deficiency anemia if heavy bleeding is caused by the tumor.
How are uterine fibroids treated?
Since most fibroids stop growing or may even shrink as you approach menopause, your health care provider may simply suggest "watchful waiting." With this approach, your health care provider monitors your symptoms carefully to ensure that there are no significant changes and that the fibroids are not growing.
If your fibroids are large or cause significant symptoms, treatment may be necessary. Treatment will be determined by your healthcare provider based on:
- How old you are
- Your overall health and past health
- How sick you are
- How well you can handle specific medicines, procedures, or therapies
- How long your condition is expected to last
- Your opinion or preference
- Your desire for pregnancy
In general, treatment for fibroids may include:
- Hysterectomy. This is the surgical removal of the entire uterus. Fibroids remain the number one reason for hysterectomies in the U.S.
- Conservative surgical therapy. Conservative surgical therapy uses a procedure called a myomectomy. With this approach, fibroids are removed, but the uterus stays intact. This may allow a future pregnancy.
- Gonadotropin-releasing hormone agonists (GnRH agonists). This approach lowers your estrogen level. This triggers a "medical menopause." Sometimes GnRH agonists are used to shrink the fibroid, making surgery easier.
- Anti-hormonal medicines. Certain medicines oppose estrogen (such as progestin and Danazol), and seem to work to treat fibroids. Anti-progestins, which block the action of progesterone, are also sometimes used.
- Uterine artery embolization. Also called uterine fibroid embolization, uterine artery embolization (UAE) is a newer technique. The arteries supplying blood to the fibroids are identified, then embolized (blocked off). The embolization cuts off the blood supply to the fibroids, thus shrinking them. Healthcare providers continue to look at the long-term implications of this procedure on fertility and regrowth of the fibroid tissue.
- Anti-inflammatory painkillers. This type of medicine is often effective for women who have occasional pelvic pain or discomfort.
In some cases, the heavy or prolonged periods, or the abnormal bleeding between periods, can lead to iron-deficiency anemia. This also requires treatment.
What are the complications of uterine fibroids?
Uterine fibroids may have effects on the reproductive system, causing infertility, increased risk of miscarriage, or adverse pregnancy outcomes.
Key points about uterine fibroids
- Uterine fibroids are firm, compact tumors that are made of smooth muscle cells and fibrous connective tissue that develop in the uterus.
- Fibroids are not cancer and do not increase a woman's risk for uterine cancer.
- It is not known what causes fibroids.
- Women who are nearing menopause are at the greatest risk for fibroids. This is because of their long exposure to high levels of estrogen.
- Symptoms may include heavy and prolonged periods, bleeding between periods and pelvic pain.
- Fibroids are most often found during a routine pelvic exam.
- If treatment is needed, it may include medicines or surgery.
Tips to help you get the most from a visit to your healthcare provider:
- Before your visit, write down questions you want answered.
- Bring someone with you to help you ask questions and remember what your provider tells you.
- At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
- If you have a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your provider if you have questions.