Fibroids

This factsheet is for women who have fibroids, or who would like information about them.

Fibroids are non-cancerous growths of your womb (uterus). They are also known as uterine myomas or leiomyomas.

About fibroids

Fibroids are growths enclosed in capsules in the wall of your womb. They don't spread to other parts of your body, except in very rare circumstances.

Fibroids are very common – around one in two women will be affected at some point in their lives. However, most don't ever get any symptoms.

You may have only one fibroid or you may have many fibroids of different sizes. Fibroids can range from being very small to around the size of a basketball.

Fibroids are named according to where they are found in your womb.

• Intramural fibroids grow within the muscular wall of your womb.
• Subserous fibroids grow from the outside wall of your womb into your pelvic cavity. They can become very large.
• Submucosal fibroids grow from the inner wall of your womb into the space inside your womb.
• Pedunculated fibroids grow from the outside of your womb. These fibroids are almost free of the wall of your womb and are only attached by a narrow stalk.

Fibroid growth is very slow and can be stimulated by hormones – especially oestrogen. Fibroids tend to become smaller and reduce in number when your oestrogen levels fall, such as after the menopause.

Symptoms of fibroids

Fibroids don't usually cause symptoms. However, you may get one or more of the symptoms listed below, often depending on where the fibroid is within your womb. You may:

• have heavy periods, sometimes leading to anaemia
• feel pain in your tummy (abdomen)
• have swelling in your pelvic area
• pass urine more often than normal, or feel an urgent need to pass urine – this happens if a fibroid is pressing on your bladder
• have constipation – this happens if a fibroid is pressing on your bowel

You can get severe pain if a fibroid twists or outgrows its blood supply causing it to break down, but this is rare.

Complications of fibroids

Most women with fibroids can have a normal pregnancy and delivery; however, there can be some complications. For example, submucosal fibroids can affect your womb, which can make it more difficult for you to become pregnant.

Fibroids can sometimes cause problems such as miscarriage, premature labour and bleeding, but this is rare. If you're pregnant and have fibroids, your GP may refer you to an obstetrician (a doctor who specialises in pregnancy and childbirth) for specialist care.

It’s rare for fibroids to become cancerous, though if one suddenly grows or becomes painful this may be more concerning, especially if this happens after you have had the menopause.

Causes of fibroids

The reasons why women get fibroids aren't known. Although oestrogen seems to make fibroids grow, it's not thought to be responsible for their initial development.

You're more likely to get fibroids if you:

• are in your 30s, 40s or 50s
• are overweight
• are African-Caribbean – women of this background are three times more likely than Caucasian women to get fibroids
• don’t have any children

Diagnosis of fibroids

Most women with fibroids have no symptoms, so they often go undetected. Sometimes they are found during a routine gynaecological (vaginal) examination. If you have symptoms, such as pain or heavy periods, your doctor may do the following tests.

• An internal examination to check the size of your womb. This is because having an enlarged womb indicates that you may have fibroids.
• An ultrasound scan. This uses sound waves to produce an image of part of your womb and can confirm if you have fibroids.
• An MRI scan. This uses magnets and radiowaves to produce images of the inside of your womb.
• Hysteroscopy. This is a test that involves your doctor putting a small camera into your vagina to look inside your womb.
• Blood tests to check for anaemia.

Treatment of fibroids

If you don't have any symptoms, or if your symptoms are mild, you won't need treatment. But if you have more severe symptoms, there is a range of treatments available. Your doctor will explain which treatment is most suitable for you.

Medicines

There is no medicine that cures fibroids, but hormone-based treatments can help to relieve your symptoms. Treatment with medicines called gonadotropin-releasing hormone analogues (GnRH analogues) can lower your oestrogen levels, which usually shrinks fibroids.

If you're having surgery to remove fibroids, you may be prescribed GnRH analogues such as goserelin or leuprorelin acetate. You take these for three to four months before your operation to make it easier for your surgeon to remove the fibroids.

GnRH analogues can cause you to have an artificial menopause whilst you take them. Symptoms may include hot flushes and, if used in the long-term, osteoporosis (thinning of your bones). Therefore, you can only take GnRH analogues for a maximum of six months.

If you have very heavy or painful periods, you doctor may suggest that you take a medicine called tranexamic acid or mefenamic acid, which can help to prevent bleeding and reduce pain.

Surgery

There are a number of surgical options for treating fibroids, including those outlined below.

Uterine artery embolisation (UAE)

This procedure blocks the blood supply to a fibroid, causing it to shrink. You will have UAE under local anaesthesia, which means that feeling in the affected area is completely blocked, but you will stay awake during the operation. You may also be given a sedative to help you to relax. UAE gives relief from symptoms, such as bleeding and pain, for eight to nine out of 10 women one year after the procedure.

Endometrial ablation or resection

Endometrial ablation is a procedure to remove most of the lining of your womb or to destroy or remove an individual fibroid using energy such as microwaves or heat. During an endometrial resection, the lining of your womb or the fibroid is cut away. Endometrial ablation is typically used for heavy menstrual bleeding, but is less successful if you have many fibroids in your womb.

Myomectomy

This is an operation that removes fibroids, but leaves your womb in place. It may be done through a cut in your abdomen, or sometimes it may be possible for your surgeon to use keyhole (laparoscopic) surgery.

Myomectomy is usually only offered to women who would like the option to become pregnant in the future. As your womb isn't removed there is a chance that more fibroids will grow in the future, so you may need to have further treatment.

Hysterectomy

This is a major operation to remove your entire womb, usually via a 'bikini-line' cut in your abdomen or, if the fibroids aren't too large, through your vagina. It's not possible to get pregnant after a hysterectomy.

Produced by Krysta Munford, Bupa Health Information Team, August 2012. 

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.