Uterine Fibroids

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Uterine Fibroids



Uterine fibroids (also called leiomyomas or myomas) are benign growths of the muscle inside the uterus. They are not cancerous, nor are they related to cancer. Fibroids can cause a wide variety of symptoms, including heavy menstrual bleeding and pressure on the pelvis.


Uterine fibroids are extremely common. About 25% of women in their reproductive years have noticeable fibroids. There are probably many more women who have tiny fibroids that are undetected.
Fibroids develop between the ages of 30-50. They are never seen in women less than 20 years old. After menopause, if a woman does not take estrogen, fibroids shrink. It appears that African-American women are much more likely to develop uterine fibroids.
Fibroids are divided into different types, depending on the location. Submucous fibroids are found in the uterine cavity; intramural fibroids grow on the wall of the uterus; and subserous fibroids are located on the outside of the uterus. Many fibroids are so large that they fit into more than one category. The symptoms caused by fibroids are often related to their location.

Causes and symptoms

No one knows exactly what causes fibroids. However, the growth of fibroids appears to depend on the hormone estrogen. Fibroids often grow larger when estrogen levels are high, as in pregnancy. Medications that lower the estrogen level can cause the fibroids to shrink.
The signs and symptoms of fibroids include:
  • Heavy uterine bleeding. This is the most common symptom, occurring in 30% of women who have fibroids. The excess bleeding usually happens during the menstrual period. Flow may be heavier, and periods may last longer. Women who have submucous or intramural fibroids are most likely to have heavy uterine bleeding.
  • Pelvic pressure and pain. Large fibroids that press on nearby structures such as the bladder and bowel can cause pressure and pain. Larger fibroids tend to cause worse symptoms.
  • Infertility. This is a rare symptom of fibroids. It probably accounts for less than 3% of infertility cases. Fibroids can cause infertility by compressing the uterine cavity. Submucous fibroids can fill the uterine cavity and interfere with implantation of the fertilized egg.
  • Miscarriage. This is also an unusual symptom of fibroids, probably accounting for only a tiny fraction of the miscarriages that occur.
  • Pregnancy complications. Fibroids can greatly increase in size during pregnancy, because of increased levels of estrogen. They can cause pain, and even lead to premature labor.


A health care provider can usually feel fibroids during a routine pelvic examination. Ultrasound can be used to confirm the diagnosis, but this is not necessary.
Uterine fibroids are benign growths of uterine muscle and are very common. They are divided into three types, depending on the location. Submucous fibroids are found in the uterine cavity; intramural fibroids grow on the wall of the uterus; and subserous fibroids are located outside of the uterus.
Uterine fibroids are benign growths of uterine muscle and are very common. They are divided into three types, depending on the location. Submucous fibroids are found in the uterine cavity; intramural fibroids grow on the wall of the uterus; and subserous fibroids are located outside of the uterus.
(Illustration by Electronic Illustrators Group.)


Not all fibroids cause symptoms. Even fibroids that do cause symptoms may not require treatment. In the majority of cases, the symptoms are inconvenient and unpleasant, but do not result in health problems.
Occasionally, fibroids lead to such heavy menstrual bleeding that the woman becomes severely anemic. In these cases, treatment of the fibroids may be necessary. Very large fibroids are much harder to treat. Therefore, many doctors recommend treatment for moderately-sized fibroids, in the hopes of preventing them from growing into large fibroids that cause worse symptoms.
The following are possible treatment plans:
  • Observation. This is the most common plan. Most women already have symptoms at the time their fibroids are discovered, but feel that they can tolerate their symptoms. Therefore, no active treatment is given, but the woman and her physician stay alert for signs that the condition might be getting worse.
  • Hysterectomy. This involves surgical removal of the uterus, and it is the only real cure for fibroids. In fact, 25% of hysterectomies are performed because of symptomatic fibroids. By the time a woman has a hysterectomy for fibroids, she has usually endured several years of worsening symptoms. That's because fibroids tend to grow over time. A gynecologist can remove a fibroid uterus during either an abdominal or a vaginal hysterectomy. The choice depends on the size of the fibroids and other factors such as previous births and previous surgeries.
  • Myomectomy. In this surgical procedure only the fibroids are removed; the uterus is repaired and left in place. This is the surgical procedure many women choose if they are not finished with childbearing. At first glance, it seems that this treatment is a middle ground between observation and hysterectomy. However, myomectomy is actually a difficult surgical procedure, more difficult than a hysterectomy. Myomectomy often causes significant blood loss, and blood transfusions may be required. In addition, some fibroids are so large, or buried so deeply within the wall of the uterus, that it is not possible to save the uterus, and a hysterectomy must be done, even though it was not planned. There are exceptions to this, however. Sometimes, fibroids grow on a stalk (pedunculated fibroids), and these are easy to remove.
  • Medical treatment. Since fibroids are dependent on estrogen for their growth, medical treatments that lower estrogen levels can cause fibroids to shrink. A group of medications known as GnRH antagonists can dramatically lower estrogen levels. Women who take these medications for three to six months find that their fibroids shrink in size by 50% or more. They usually experience dramatic relief of their symptoms of heavy bleeding and pelvic pain.
Unfortunately, GnRH antagonists cause unpleasant side effects in over 90% of women. The therapy is usually used for only three months, and should not be used for more than six months because the risk of developing brittle bones (osteoporosis) begins to rise. Once the treatment is stopped, the fibroids begin to grow back to their original size. Within six months, most of the old symptoms return. Therefore, GnRH agonists cannot be used as long-term solution. At the moment, treatment with GnRH antagonists is used mainly in preparation for surgery (myomectomy or hysterectomy). Shrinking the size of the fibroids makes surgery much easier, and reducing the heavy bleeding allows a woman to build up her blood count before surgery.
Fibroids can cause problems during pregnancy because they often grow in size. Large fibroids can cause pain and lead to premature labor. Fibroids cannot be removed during pregnancy because of the risk of injury to the uterus and hemorrhage. GnRH antagonists cannot be used during pregnancy. Treatment is limited to pain medication and medication to prevent premature labor, if necessary.


Many women who have fibroids have no symptoms or have only minor symptoms of heavy menstrual bleeding or pelvic pressure. However, fibroids tend to grow over time, and gradually cause more symptoms. Many women ultimately decide to have some form of treatment. Currently, hysterectomy is the most popular form of treatment.


Uterine fibroids cannot be prevented.



Friedman, Andrew J. "Uterine Fibroids." In Primary Care of Women, edited by Karen J. Carlson and Stephanie A. Eisenstat. St. Louis: Mosby-Year Book,Inc., 1995.

Key terms

Anemia — Low blood count.
GnRH antagonists — A group of medications that affect the reproductive hormones. These medications are used to treat fibroids, endometriosis, and infertility.
Hysterectomy — Removal of the uterus (with or without removal of the ovaries) by surgery. The surgery can be performed through an incision in the abdomen, or the uterus can be removed through the vagina.
Menopause — The end of the reproductive years, signaled by the end of menstrual periods. Also known as "the change."
Osteoporosis — Brittle bones commonly found in elderly women.

Patient discussion about Uterine Fibroids

Q. uterine fibroids. Whats the best way to deal with them? My doctor says hysterectomy? What about my hormones?

A. Yes, drugs that suppress the levels of the female sex hormones (estrogen) are successful for treating uterine fibroids. However, the relief is only temporary and the fibroids recur once the treatment is stopped. In addition, these treatments cause side effects similar to menopause.

Surgery is the definitive treatment, especially for complications such as bleeding or pain, and when there's a suspicion for malignancy.

You may read more here: http://www.nlm.nih.gov/medlineplus/ency/article/000914.htm

More discussions about Uterine Fibroids
References in periodicals archive ?
A European series of trials called the PGL4001 (Ulipristal Acetate) Efficacy Assessment in Reduction of Symptoms Due to Uterine Leiomyomata (PEARL) trials (9) used a double-blind, randomized study model (the gold standard in clinical trials) to assess Esmya's impact.
Estrakial and progesterone binding in uterine leiomyomata and in normal uterine tissues.
Obstetric outcomes in women with sonographically identified uterine leiomyomata. Obstet Gynecol.
Cytogenetic abnormalities in uterine leiomyomata. Obstet Gynecol 1991;77:923-6.
Regression of uterine leiomyomata in response to the antiprogesterone RU 486.
Routine hysterectomy for large asymptomatic uterine leiomyomata: A reappraisal.
Association of exposure to phthalates with endometriosis and uterine leiomyomata: findings from NHANES, 1999-2004.
Does pelvic magnetic resonance imaging differentiate among the histologic subtypes of uterine leiomyomata? Fertil Steril 1998; 70:580-587.
Reiter, "Uterine leiomyomata: etiology, symptomatology, and management," Fertility and Sterility, vol.
Diverse complications have been reported in association with the growth and medical treatment of uterine leiomyomata. Infarction and necrosis may be common and incite complications from parasitic vascular attachment, pain and thrombosis.
Uterine leiomyomata and fecundability in the Right from the Start study.