Fibroids are benign (non-cancerous) tumours that grow in or around the womb (uterus). 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 fibroids
Fibroids can grow anywhere in the womb. The five main types of fibroids are described below.
- Intramural fibroids develop in the muscle wall of the womb and they are the most common type of fibroids found in women.
- Subserosal fibroids grow outside the wall of the womb into the pelvis and can become very large.
- Submucosal fibroids develop in the muscle beneath the inner lining of the womb wall and they grow into the middle of the womb.
- Pedunculated fibroids grow from the outside wall of the womb and are attached to the womb wall by a narrow stalk.
- Cervical fibroids develop in the wall of the cervix (the neck of the womb).
How common are fibroids?
Fibroids are common, with at least one in four women developing them at some stage in their life. They most often occur in women who are from 30 to 50 years old.
Fibroids tend to develop more frequently in women who are of Afro-Caribbean origin and in women who are overweight. It is thought that they occur in heavier women as a result of higher oestrogen levels.
Outlook
In many cases, fibroids do not cause symptoms and treatment is not required. Over time, fibroids will often shrink and disappear without any treatment.
However, sometimes fibroids can cause symptoms, such as pain or heavy bleeding. In such cases, medication may be prescribed. If this proves ineffective, surgical or non-surgical techniques may be recommended.
In very rare cases, malignant (cancerous) growths on the smooth muscles inside the womb can develop. These cancerous growths are known as leiomyosarcomas (see the Complications section for further details).
Benign
Benign refers to a condition that should not become life-threatening. In relation to tumours, benign means not cancerous.
Womb
The uterus (also known as the womb) is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.
Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.
Cervix
The cervix is at the lower end of the womb. It connects the womb with the vagina.
Malignant
Malignant is a term used to describe a life-threatening or worsening condition. In the case of tumours, malignant means cancerous.
