Doctors believe that uterine fibroids develop from a stem cell in the smooth muscular tissue of the uterus (myometrium). A single cell divides repeatedly, eventually creating a firm, rubbery mass distinct from nearby tissue. The reason why this happens or their exact cause is not entirely clear. However, research has identified several factors that may contribute to the development of fibroids, including:
- Hormones: Estrogen and progesterone, two hormones that regulate the menstrual cycle, appear to play a role in the development of fibroids. These hormones can stimulate the growth of uterine tissue, which can lead to the formation of fibroids.
- Genetic changes: Many fibroids contain changes in genes that differ from those in typical uterine muscle cells.
- Age and reproductive status: Fibroids are more common in women who are in their 30s and 40s and have not yet reached menopause. They can shrink after menopause when hormone levels decrease.
- Obesity: Being overweight or obese may increase the risk of developing fibroids.
- Other growth factors. Substances that help the body maintain tissues, such as insulin-like growth factor, may affect fibroid growth.
- Extracellular matrix (ECM). ECM is the material that makes cells stick together, like mortar between bricks. ECM is increased in fibroids and makes them fibrous. ECM also stores growth factors and causes biologic changes in the cells themselves.
Risk factors
There are few known risk factors for uterine fibroids, other than being a woman of reproductive age. Factors that can have an impact on fibroid development include:
- Race. Although all women of reproductive age could develop fibroids, black women are more likely to have fibroids than are women of other racial groups. In addition, black women have fibroids at younger ages, and they’re also likely to have more or larger fibroids, along with more-severe symptoms.
- Heredity. Fibroids may run in families, suggesting that there may be a genetic predisposition to developing these growths. If your mother or sister had fibroids, you’re at increased risk of developing them.
- Other factors. Other factors that may contribute to the development of fibroids include a vitamin D deficiency; having a diet higher in red meat and lower in green vegetables, fruit and dairy, early onset of menstruation, and a history of uterine infections; and drinking alcohol, including beer. These appear to increase your risk of developing fibroids.
It’s important to note that many women with fibroids do not experience any symptoms, and treatment may not be necessary. However, for those who do experience symptoms such as heavy or painful periods, frequent urination, or pelvic pain, there are a range of treatment options available, including medication, non-surgical procedures, and surgery.