What are Fibroids?
Uterine fibroids are growths of the muscle wall of the womb (uterus). They are found in approximately 20% of women older than 30 years. Most fibroids are benign (do not cause cancer). Some fibroids grow inwards towards the womb and others grow outwards into the pelvic (lower trunk) cavity. They can be any size from a pea to the size of a grapefruit.

How do you get Fibroids?

  • The cause of fibroids is unknown, but may be related in part to changes in oestrogen and progesterone levels.  
  • The risk of fibroids decreases as the number of children borne to a woman increases.  
  • The use of oral contraceptives for a long period also decreases the risk of developing fibroids.  
  • A high body weight increases the risk of developing fibroids.  
  • Doctors have long recognised that fibroids are dependent on female sex hormones (chemical signals carried in the blood called oestrogens) for maintaining their growth and size. Once a woman reaches the menopause, fibroids will usually shrink.

How serious are Fibroids?
The presence of fibroids may cause symptoms such as heavy periods or menstruation (menorrhagia), feelings of bloating and heaviness, iron deficiency (anaemia) and pelvic discomfort and may lead to infertility and miscarriage. Symptoms have been observed in between 20-50% of sufferers, the rest being symptom-free. Ultrasound scans are usually used to diagnose fibroids.

How long do Fibroids last?
Fibroids may last throughout reproductive life. These growths are rarely found before puberty; they increase in size during pregnancy. Fibroids stop growing and shrink after the menopause.

How are Fibroids treated?
The treatment options for uterine fibroids depend on the age of the patient, the patient’s desire to retain their fertility and whether they have symptoms or not. Most fibroids do not require any treatment at all.

  • Traditionally, surgery has been used in the treatment of the disease. This involves:
    • Cutting out fibroids from the womb (called a myomectomy) in younger patients and in patients wanting children.      
    • Removal of the womb (called a hysterectomy) particularly in the older patients with symptoms or for those women whose families are complete.


  • The development of medicines, called luteinising hormone-releasing hormone (LHRH) analogues, has enabled a combined surgical and medical approach. These work by stopping the production of female sex hormones, particularly oestrogen. They are given as a pellet, injected under the skin of the abdomen (trunk), which slowly dissolves (over 1 to 3 months) and is absorbed by the body. Often, a course of LHRH analogue treatment is followed by surgery.


  • Overall, the medical treatment reduces uterine and fibroid size (volumes), improves the anaemia and reduces the symptoms associated with fibroids. In some patients, it may allow the fibroids alone to be removed rather than the whole womb.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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