Uterine fibroids are tumors or lumps made of muscle cells and other tissue that grow within the wall of the uterus. Fibroids may grow as a single tumor or in clusters.
A single fibroid can be less than one inch in size or can grow to eight inches across or more. A bunch or cluster of fibroids can also vary in size.
Where do uterine fibroids grow?
Most fibroids grow within the wall of the uterus. Health care providers put fibroids into three groups based on where they grow:
•Submucosal (pronounced sub-myou-co-sul) fibroids grow just underneath the uterine lining.
•Intramural (pronounced in-tra-myur-ul) fibroids grow in between the muscles of the uterus.
•Subserosal (pronounced sub-sir-oh-sul) fibroids grow on the outside of the uterus.
Some fibroids grow on stalks (also called peduncles, pronounced ped-uncles) that grow out from the surface of the uterus, or into the cavity of the uterus.
What are the symptoms of uterine fibroids?
Many women don’t feel any symptoms with uterine fibroids. But fibroids can cause the following symptoms:
•Heavy bleeding or painful periods
•Bleeding between periods
•Feeling “full” in the lower abdomen—sometimes called “pelvic pressure”
•Urinating often (results from a fibroid pressing on the bladder)
•Pain during sex
•Lower back pain
•Reproductive problems, such as infertility, multiple miscarriages, and early onset of labor during pregnancy
What causes uterine fibroids?
Currently, we know little about what causes uterine fibroids. Scientists have a number of theories, but none of these ideas explains fibroids completely. Most likely, fibroids are the end result of many factors interacting with each other. These factors could be genetic, hormonal, environmental, or a combination of all three. Once we know the cause or causes of fibroids, our efforts to find a cure or even prevent fibroids will move ahead more quickly.
Does having uterine fibroids mean that a woman will be infertile or unable to have children?
In some cases, fibroids can prevent a woman from getting pregnant through natural methods. However, advances in treatments for fibroids and infertility have greatly improved the chances for a woman to get pregnant, even if she has uterine fibroids.
Researchers are still looking into what role, if any, uterine fibroids play in infertility. Currently, though, there are few answers. One study’s results suggest that only submucosal fibroids have a negative impact on fertility (Pritts 2001), but these results are not yet confirmed. The relationship between fibroids and infertility remains a very active research area.