Uterine Fibroids

If you are a woman between 30 and 50 years of age, there’s a strong chance that you or someone close to you is suffering from uterine fibroids. At least 25 percent of women in the United States have symptoms of uterine fibroids. In fact, about 70 percent of Caucasian women and more than 80 percent of African-American women have developed fibroids by the time they’re 50 years old. Nearly 10 million women of reproductive age in the US have symptomatic uterine fibroids. That is about 1 out of every 4 women.

What are Uterine Fibroids?

Benign uterine fibroids (medically known as uterine leiomyomata) or myoma are common, non-cancerous (benign) tumors of the uterus consisting of smooth muscle cells and connective tissue. The uterus itself is a muscle, and fibroids are round balls of this same smooth muscle. A woman may have one fibroid or many fibroids. They are typically detected between 2 and 10 cm but can grow as large as 30 cm. In women undergoing surgery for a fibroid, there is a reported .20% (1/500) chance the fibroid may harbor a malignancy called a leiyomyosarcoma. Depending on your age, there is only a .01-.1% (1/1000 to 1/1500) occurrence of a malignancy inside a fibroid. There is no reliable way of clinically or radiographically determining if a fibroid contains such malignant tissue.

Where are the fibroids located in the uterus?
Along with size, the location of uterine fibroids affects symptom severity and treatment decisions. There is a detailed classification of fibroid location by FIGO but the terms are summarized below. The definitive diagnosis of fibroids requires an ultrasound or MRI scan:

  • Submucosal fibroids - The uterus has a centrally located endometrial cavity, where babies grow. This cavity is lined with a "mucosal" layer of cells, somewhat like the moist lining of the stomach or the vagina. Some fibroids grow just beneath this mucosal lining. As these fibroids and the surrounding glands are very hormonally responsive, submucosal fibroids typically present with heavy bleeding during and perhaps in between menstrual cycles. These fibroids can also cause infertility by distorting the endometrial cavity so the embryo cannot implant or grow properly or grow on the uneven endometrium.
  • Intramural fibroids – These fibroids grow entirely within the muscular wall of the uterus and do not grow near the endometrium or the outer serosal layer of the uterus. Depending on their size, these fibroids can cause mass effect on the bladder or rectum, cause the abdominal wall to protrude outward making a woman almost look like she is pregnant, cause pain during intercourse, or cause heavy bleeding during the menstrual cycles. These fibroids may have a negative impact on implantation and clinical pregnancy rates possibly through altered uterine muscle contractility.
  • Subserosal fibroids – The outside of the uterus is covered with a “skin” of serous, non-secretory cells. Some fibroids grow just under this outer surface of the uterus. These fibroids can cause similar symptoms to the intramural fibroids. These fibroids usually do not affect fertility.
  • Pedunculated fibroids – Some submucosal fibroids can partially extend in to the endometrium via a stalk and cause heavy bleeding during and in between menstrual cycles and contribute to infertility. Some subserosal fibroids grow outward, away from the uterus, via a stalk to the uterus and can compress surrounding anatomic structures such as the bladder, rectum, or other pelvic and abdominal structures.

What causes Uterine Fibroids?

The cause of fibroids is unknown, however a combination of hormonal, genetic, and environmental factors is associated with the chance that a woman will develop symptomatic fibroids:

  • Hormones - Fibroids are associated with increased estrogen production. Early menarche and increased frequency of menses may increase the chance of developing uterine fibroids. They are rare in women less than 20 years of age as well as in postmenopausal women. Estrogen levels vary with menstruation, with menopause, and with some medications
  • Genetics - Family history of fibroids increases the chance of developing fibroids.
  • Environment - Alcohol consumption and a sedentary lifestyle have been associated with fibroids. Researchers are investigating how environmental toxins affect gene activity in the uterus.
  • Ethnicity - Not only are African-American women more likely to develop fibroids, their fibroids occur at a younger age, and are often larger and more numerous than in other ethnic groups. Asian women have a lower incidence of symptomatic fibroids.
  • BMI - Women who are overweight or obese, based on their BMI (body-mass index), have a slightly higher risk of developing fibroids.
  • Pregnancy - Women who have given birth seem to have a lower risk of developing uterine fibroids. Recent information indicates that pregnancy may protect against fibroids – one theory is that fibroids are lost during the uterine changes (involution) in the weeks following childbirth.
  • Clinical conditions - Hypertension and diabetes increase the risk for developing fibroids

What are the symptoms of Uterine Fibroids?

  • Abnormal Uterine bleeding - Periods may be abnormally heavy and last more than a week. Some women are concerned about socially embarrassing bleeding and hesitate to engage in their normal activities. Irregular bleeding may also occur between menstrual cycles Heavy and prolonged bleeding may be severe enough to cause anemia. Submucosal and intracavitary fibroids are associated more with heavy bleeding, even despite smaller sizes.
  • Bulk Symptoms - With larger fibroids, patients may feel increased pressure in the pelvis, bowel dysfunction such as constipation, and urinary frequency/urgency Patients ,may also look pregnant as the anterior abdominal wall is displaced outward by a large fibroid.
  • Infertilty - Most women with fibroids do not have fertility problems. However, submucosal/intracavitary fibroids have been shown to cause infertility by negatively affecting implantation and clinical pregnancy rates while also associated with higher miscarriage rates. Intramural fibroids may also less frequently interfere with implantation and clinical pregnancy rates.

Fibroid Research

  • The Management of Uterine Fibroids in Women With Otherwise Unexplained Infertility - From the abstract's objective section, this paper was created "to provide recommendations regarding the best management of fibroids in couples who present with infertility. Usual and novel treatment options for fibroids will be reviewed with emphasis on their applicability in women who wish to conceive."
  • The Management of Uterine Leiomyomas - From the abstract's objective section, this paper was created "The aim of this guideline is to provide clinicians with an understanding of the pathophysiology, prevalence, and clinical significance of myomata and the best evidence available on treatment modalities."
  • Uterine Fibroids - This paper "begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the author’s clinical recommendations."