Cardiovascular and Interventional Radiological Society of Europe

Uterine fibroids


Uterine fibroids are the most common tumours of the female genital tract. You might hear them referred to as “fibroids” or by several other names, including leiomyoma, myoma or fibromyoma. Fibroids are non-cancerous (benign) growths that develop in the muscular wall of the uterus. Fibroids do not always cause symptoms. Nevertheless their size and location can lead to problems for some women, including heavy bleeding, pelvic pain, and pressure symptoms (bloating, swelling, urinary frequency). Fibroids may also be associated with infertility.

Uterine fibroids are very common, although often they are very small and cause no problems. From 20-40% of women aged 35 and over have uterine fibroids of a significant size. African-American women are at a higher risk: as many as 50% have fibroids of a significant size.

Fibroids range greatly in size, from very tiny to the size of a cantaloupe melon or larger. In some cases, they can cause the uterus to grow to the size of a five-month pregnancy or more. Fibroids may be located in various parts of the uterus. In most cases, there is more than one fibroid in the uterus. There are three primary types of uterine fibroids.

  • Subserosal fibroids
  • Intramural fibroids
  • Submucosal fibroids

Subserosal fibroids

These fibroids develop under the outside covering of the uterus and expand outward through the wall, giving the uterus a lumpy appearance. They typically do not affect a woman’s menstrual flow, but can cause pelvic pain, back pain and pressure on surrounding organs (leading to urinary frequency or constipation). The subserosal fibroid can develop a stalk or stem-like base, making it difficult to distinguish from an ovarian mass. These are called pedunculated. The correct diagnosis can be made with either an ultrasound or magnetic resonance (MR) exam.

Intradmual fibroids

These fibroids develop within the lining of the uterus and expand inward, increasing the size of the uterus, and making it feel larger than normal in a gynaecological internal exam. These are the most common fibroids. Intramural fibroids can result in heavier menstrual bleeding and compression symptoms that many women experience.

Submucosal fibroids

These fibroids develop in the uterine cavity. These are the least common fibroids, but they tend to cause the most problems. Even a very small submucosal fibroid can cause heavy bleeding, and very heavy and prolonged periods. They may also interfere with fertility.


Most fibroids do not cause symptoms — only 10-20% of women with fibroids ever require treatment. Depending on location, size and number of fibroids, a woman might experience the following:

• Pelvic pain
• Pelvic pressure or heaviness caused by the bulk or weight of the fibroids pressing on nearby structures
• Pain in the back or legs as the fibroids press on nerves that supply the pelvis and legs
• Pain during sexual intercourse
• Bladder pressure leading to a constant urge to urinate
• Pressure on the bowel, leading to constipation and bloating
• Abnormally enlarged abdomen
• Heavy, prolonged menstrual periods and unusual monthly bleeding, sometimes clots. This often leads to anaemia.


If you have large fibroids, your doctor may suspect this after physically examining you, but most fibroids are diagnosed by ultrasound. In some cases, when planning treatment, the doctor will use MRI to characterise the fibroids and assess their response to therapy.


There are a number of treatments available, some of which will preserve your uterus and some of which will not. The treatment you will be prescribed depends on your age and if you are planning to have a baby.

Techniques which preserve your uterus include blocking the blood supply to the uterus through a small artery hole (uterine fibroid embolisation) or removing the fibroid (myomectomy). You may be given hormonal treatments for the fibroids.

Choosing the most appropriate treatment depends on what symptoms you have, the impact of these symptoms on your quality of life, and whether you are trying to have a baby now or in the future.