Fibroids are benign (non-cancerous) tumours that grow in or around the uterus (womb). The growths are made up of muscle and fibrous tissue and can vary in size. Fibroids are sometimes known as uterine myomas or fibromyomas.
Fibroids usually develop during a woman's reproductive years (from approximately 16 to 50 years of age). They are linked to the production of oestrogen, which is the female reproductive hormone.
Types of fibroid
Fibroids can grow anywhere in the uterus. The main types of fibroid are:
- intramural fibroids develop in the muscle wall of the uterus and are the most common type of fibroid.
- subserosal fibroids grow outside the wall of the uterus into the pelvis.
- submucosal fibroids develop in the muscle beneath the inner lining of the uterine wall and grow into the middle of the womb.
- pedunculated fibroids grow from the outside wall of the womb and are attached to the uterine wall by a narrow stalk.
How common are fibroids?
Uterine fibroids are very common amongst women of childbearing age, with at least one in four women developing them at some stage in their life.