The Definition and Causes of Fibroid Tumors

Fibroid tumors grow in the uterus, and they seem to be most common during a woman's fertile years, especially after the age of 30. Such uterine tumors are rarely cancerous, but they can grow to be quite large and uncomfortable. Fibroid tumors can range in size from quite small (measured in millimeters) to large (many centimeters.) Large fibroid tumors can distort the urterus, making it appear lumpy when visualized during a pelvic ultrasound.

Although they can distort the overall appearance of the uterus, uterine fibroids are actually quite smooth, rounded, and well-defined. These tumors are overgrowths of the muscular, middle layer of the uterus, the myometrium. When they project into the endometrium (submucosal), they can cause heavy menstrual bleeding. Fibroid tumors that project outward (subserosal) can press on the bladder or rectum, causing problems with these organs. One other type of fibroid actually grows outside of the uterus and is attached by a very narrow band of blood vessels. This type of fibroid is said to be "pedunculated." Fibroids can cause a heavy, full feeling in the abdomen and can be singular or multiple in number.

Causes of Fibroid Tumors

Some theories about the causes of uterine fibroid tumors are conclusive, while others are only speculative. There is conclusive evidence that fibroids can be caused by:

• The hormone estrogen: uterine fibroids grow in the presence of estrogen. This is why they tend to develop and grow during the fertile years of a woman's life (when she has the highest levels of estrogen in her body), and they stop growing and new fibroids usually don't develop after menopause.
• Heredity: apparently scientists have found gene mutations in fibroid tissue cells. A patient's risk of developing fibroids increases if a close family member (mother and/or sister) has the tumors.
• Race: for reasons unknown, African-American women are more likely to develop fibroids than any other race. They are more likely to have larger and/or multiple fibroids as well.

Possible factors that decrease the risk for developing fibroids (speculative):

• Oral contraceptives
• Pregnancy (although some theorize that they actually grow during this time, due to increased estrogen levels)
• Being athletic (whereas being overweight has been thought to increase the odds of developing fibroids)

Symptoms of Uterine Fibroid Tumors

• Abdominal or pelvic pressure, fullness, or chronic pain
• Bladder problems such as difficulty emptying or an increase in urgency
• Difficulty moving bowels
• Very heavy and/or painful periods
• Bleeding between periods

If you experience some or all of these symptoms, or if you have a family history of fibroids, you might want to consider visiting your gynecologist for further evaluation.

References: Medline Plus Medical Encyclopedia, MayoClinic.com

Uterus with Fibroid Tumors

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