Uterine Fibroids

Uterine fibroids at a glance

  • Uterine fibroids are small, smooth muscle tumors in and around the uterus that usually occur in and after a woman’s late 40s.
  • They typically affect up to 80 percent of women but are only problematic in about 25 percent of cases.
  • Uterine fibroid tumors are noncancerous 99 percent of the time.
  • Fibroids can alter the functioning of the uterus, can cause abnormal uterine bleeding patterns, and may cause infertility as well as problems in pregnancy.
  • Treatment typically involves surgeries such as a hysterectomy or myomectomy.

What are uterine fibroids?

Uterine fibroids, also known as uterine myomas or leiomyomas, are small growths that develop on and around the uterus. Uterine fibroids are muscular tumors that are benign in 99 percent of cases and do not indicate cancer or an increased risk of cancer. Uterine fibroids are fairly common, occurring in about 80 percent of women, though they only cause problems in about 25 percent of cases.

Depending on the location, uterine fibroids can cause different reproductive issues, including infertility and difficulty with maintaining pregnancy and may complicate delivery. Roughly 5-10 percent of infertile women have uterine fibroids.

Some fibroids can alter the shape of the uterus and cervix, impacting the movement of sperm. Other fibroids can block blood flow to the uterus, making it harder for embryos to implant on the uterine wall and establish a successful pregnancy. Some fibroids can even block the fallopian tubes, preventing a fertilized embryo from reaching the uterus.

During pregnancy, uterine fibroids increase the chance for a miscarriage or premature birth. They can also change the fetus’ position in the uterus, creating the need for a cesarean section birth.

Uterine fibroids vary in size, and can range from being microscopic to being larger than an orange, though very large fibroids are rare. Women can have one or several and they can all be different sizes. In addition to the uterus, they can also develop in the cervix, bladder and other organs near the uterus.

There are three main types of uterine fibroids:

  • Subserosal fibroids grow from the wall of the uterus outward and can create pressure on the bladder, bowel and intestine. These fibroids can cause bloating, abdominal pressure, cramping and pelvic pain.
  • Intramural fibroids grow within the muscle of the uterus and can cause pressure-like symptoms and, occasionally, heavy menstrual bleeding.
  • Submucosal fibroids grow from just underneath the uterine lining into the uterine cavity and can cause bleeding, pain or infertility.

Sometimes a fibroid grows from a stalk-like structure called a pedicle that sticks out from the uterus or into the uterine cavity. These are called pedunculated fibroids.

Cause of uterine fibroids

The actual formation of the fibroid is thought to be an abnormal muscle cell in the uterus that multiplies quickly under the influence of estrogen. Doctors don’t know exactly what causes uterine fibroids but do know that their growth is affected by the hormones estrogen and progesterone, which are also suspected of having a role in the formation of uterine fibroids.

For example, those hormone levels are high during pregnancy when an influx of estrogen and progesterone occurs. And anti-hormone medications cause uterine fibroids to shrink. Fibroids also stop growing or shrink when a woman reaches menopause, secondary to the decreased estrogen and progesterone levels.

There are several risk factors involved with developing fibroids:

  • Age is an important factor; developing fibroids becomes more common with age, up until menopause. Fibroids often begin to naturally reduce in size after menopause.
  • A genetic link can cause uterine fibroids to run in certain families, especially in identical twins. If a woman’s mother had fibroids, her chance of developing them triples.
  • African-American women are more likely to have uterine fibroids than women of other races. These women tend to develop uterine fibroids at a younger age and have an increased chance of having more and larger fibroids.
  • A diet with more red meat and alcohol and less green vegetables may also lead to an increased risk, as will obesity.

Symptoms of uterine fibroids

Many women with uterine fibroids do not experience any symptoms and are not even aware that they have fibroids. Because uterine fibroids can develop in different areas of the uterus, many women will have different, location-based symptoms. Women who do show symptoms often experience:

  • Longer and heavier menstrual bleeding
  • Pressure or pain in the pelvic region
  • Frequent urination, difficulty with emptying the bladder and constipation
  • Lower back pain
  • Abdominal swelling similar to pregnancy

Diagnosis & treatment of uterine fibroids

If the patient’s symptoms align with the possibility of fibroids, the doctor will typically perform a pelvic exam to check the size of the uterus. He or she may also order an ultrasound or another imaging test.

The type of treatment for uterine fibroids usually depends on several factors, such as age or any future plans of pregnancy. The treatments also vary based on the size and location of the fibroids and on the level of discomfort that they cause.

For cases involving low and mild discomfort, medication is commonly used to control the symptoms. Some medications can halt the growth of fibroids, but they will not remove them.

For more severe discomfort, the most common form of treatment is surgery. Typically, those include surgeries such as abdominal myomectomy and hysterectomy. The whole uterus is removed in a hysterectomy, whereas only the fibroids are removed in a myomectomy, allowing the possibility of a future pregnancy.

Minimally-invasive myomectomy such as robotic myomectomy involves only small incisions and allows the uterus to remain intact, which can help preserve fertility. An open myomectomy requires much more healing time, as the actual muscle inside the uterus is cut. Because the entire uterus is removed in a hysterectomy, there is no possibility of a future pregnancy.

A more recent minimally-invasive treatment approach is through the use of focused ultrasound, which may decrease the size of an existing fibroid. This approach is evolving, and currently is available in only select patient candidates, based on size and location of the fibroids.

Risks of treatment

All surgeries carry risks and possible complications. Hysterectomies and myomectomies may possibly damage:

  • The urinary tract
  • The bladder
  • The rectum
  • Or other pelvic structures

This damage may require further surgery to correct. With a myomectomy, there is a risk of scar tissue formation in the uterus, which could lead to infertility. Bands of scar tissues can also form outside of the uterus and these adhesions can interact with other structures, leading to a blocked fallopian tube or intestine. There is also a risk of infection to the uterus, fallopian tubes or ovaries.

The scar tissue from a previous myomectomy may call for a cesarean section during childbirth to avoid a uterine rupture. Rarely, a myomectomy does not heal properly and eventually leads to a corrective hysterectomy.


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