What Are Fibroids?

What Are Fibroids?

These information pages explain what fibroids are, how they can affect your health and what your options are for treatment.


Fibroids are the most common growths in a woman's reproductive system.

Fibroids or myomas (leiomyoma in medical terminology) are well-circumscribed tumours that grow on the outside, inside or within the smooth muscle in the wall of the womb (uterus).
Other names for these tumors include

  • fibromyomas
  • fibromas
  • myofibromas
  • myomas


They are arising from the smooth muscle layer (myometrium) of the uterus

In addition to smooth muscle, leiomyomas are also composed of extracellular matrix (i.e., collagen, proteoglycan, fibronectin).


Fibroids can be as small as a apple seed and can grow as large as a melon.

Doctors talk about the size of a uterus enlarged by fibroids the same way they talk about the size of a pregnant uterus.
So when a fibroid stretches the uterus to a 12- to 14-week size, the uterus is about the same size it would be if you were 12 to 14 weeks pregnant.
TThis refers to a fibroid about the size of a small melon, or to several smaller fibroids.

The average affected uterus has 6 to 7 fibroids.

They are not cancerous (benign) and are made up of muscle fibre.

In very rare cases, a rapidly growing fibroid may become cancerous.

Many women with fibroids have no symptoms at all, while others have symptoms ranging from heavy bleeding and pain to incontinence or infertility.

Approximately 30% of women have fibroids large enough to cause symptoms.
Studies suggest that many more women have fibroids but most fibroids those remain small and do not cause symptoms (signs)?so do not require any treatment..

They may require treatment in the following circumstances:

  • fibroids are growing large enough to cause pressure on other organs, such as the bladder or the bowel/span>
  • fibroids are growing rapidly
  • fibroids are causing abnormal bleeding
  • ffibroids are causing problems with fertility


Since the estrogen appears to encourage their growth, fibroids usually shrink at menopause and rarely cause problems that require treatment after this time.