Home | Print this page | Print whole leaflet

Fibroids

Fibroids are the most common growths in a woman's reproductive system. Many women with fibroids have no symptoms at all, while others have symptoms ranging from heavy bleeding and pain to incontinence or infertility. These information pages explain what fibroids are, how they can affect your health and what your options are for treatment. For more information on heavy bleeding or hysterectomy, visit our pages on these topics.

What are fibroids?

Fibroids are tumours that grow in the uterus (womb). They are benign, which means they are not cancerous, and are made up of muscle fibre. Fibroids can be as small as a pea and can grow as large as a melon. It is estimated that 20-50% of women have, or will have, fibroids at some time in their lives. They are rare in women under the age of 20, most common in women in their 30s and 40s, and tend to shrink after the menopause.

Although the exact cause of fibroids is unknown, they seem to be influenced by oestrogen. This would explain why they appear during a woman's middle years (when oestrogen levels are high) and stop growing after the menopause (when oestrogen levels drop).

According to US studies, fibroids occur up to nine times more often in black women than in white women, and tend to appear earlier*. The reason for this is unclear. Also women who weigh over 70kg may be more likely to have fibroids. This is thought to be due to higher levels of oestrogen in heavier women.

In the past, the contraceptive pill was thought to increase the risk of fibroids, but that was when the pill contained higher levels of oestrogen than it does today. Some studies suggest that the newer combined pill (oestrogen and progestogen) and the mini pill (progestogen only) may actually help prevent or slow the growth of fibroids.

Types of fibroids

Fibroids are categorised by where they grow in the uterus (see illustration -->):

Intramural — these grow in the wall of the womb and are the most common type of fibroid.

Subserous—- these fibroids grow from the outer layer of the womb wall and sometimes grow on stalks (called pedunculated fibroids). Subserous fibroids can grow to be very large.

Submucous — submucous fibroids develop in the muscle underneath the inner lining of the womb. They grow into the womb and can also grow on stalks which, if long enough, can hang through the cervix.

Cervical — cervical fibroids grow in the wall of the cervix (neck of the womb) and are difficult to remove without damaging the surrounding area.

If you have fibroids, you may have one or many. You may also have one type of fibroid or a number of different types.

Fibroids — prevention

As the cause of fibroids is still unknown, there are no clear guidelines for preventing them. However, there are some things you could do that may help reduce your risk:

• Keep your weight in check. This will minimise oestrogen levels in your body.
• Eat green vegetables and fruit, and avoid red meat. An Italian study found that women who eat little meat but a lot of green vegetables and fruit seem to be less likely to develop fibroids than women who eat a lot of red meat and few vegetables.
• Some studies suggest the combined pill may protect against fibroids by keeping hormone levels from peaking and falling. The pill comes with its own set of side effects, however, so talk to your doctor about whether it’s right for you.

* This information is based on studies involving black and African American women. The papers do not identify more specific ethnic backgrounds. We found no similar UK studies.

Top | Next Page

Written by Tamara Beus and published in printed format (2001) by Women's Health

This leaflet is protected by Copyright © Women's Health. You may print off one copy for personal use only.