Fibroids

Fibroids are benign (non-cancerous) tumours of the womb. They are also known as myomas or fibromyomas. They are growths of smooth muscle and fibrous tissue.

The size of fibroids can vary from as small as a pea to that of a melon. At least one in five women develop a fibroid at some stage of their life, usually between the ages of 30-50 years old. Fibroids are more common in women who are overweight and women of Afro-Caribbean origin.

Fibroids are named according to where they are found in the womb. There are four types:

• Intramural fibroids are found in the wall of the womb and are the most common type of fibroids found in women.
• Subserosal fibroids are found growing outside the wall of the womb and can become very large. They can also grow on stalks (called pedunculated fibroids).
• Submucosal fibroids are found in the muscle beneath the inner lining of the womb wall.
• Cervical fibroids are found in the wall of the cervix (neck of the womb).

In very rare cases, malignant (cancerous) growths on the smooth muscles inside the womb can develop, called leiomyosarcoma of the womb.

The majority of women with fibroids show no symptoms. Many women are unaware that they have fibroids. However,  if symptoms develop, you may experience one or more of the following:

• heavy or painful periods in some cases this can lead to anaemia,
• discomfort, or swelling, in your lower abdomen, particularly if your fibroids are large,
• backache, or pains in your legs,
• urinating frequently, usually if your fibroids are pressing on your bladder,
• constipation which can be caused by the fibroids pressing on your rectum (large intestine leading to your anus), and
• pain or discomfort during sex this is usually if your fibroids are growing near your vagina (or lower part of your cervix).

In some cases, you may have repeated miscarriages or infertility problems. Very rarely fibroids can cause problems during pregnancy and labour.

Fibroids are smooth muscle growths that occur during a woman's reproductive years (usually between the ages of 16 and 50). During this time the levels of oestrogen and progesterone are at their highest. Fibroids tend to swell when oestrogen levels are particularly high, for example, during pregnancy. They are also known to shrink when oestrogen levels are particularly low, such as after a woman has experienced the menopause. However, the exact cause of fibroids is still unknown.

As fibroids rarely have symptoms, they are often found during a routine gynaecological (vaginal) examination.

If fibroids are suspected, an ultrasound scan can be used to confirm a diagnosis. It can also rule out any other possible causes for your symptoms. For example, if you are experiencing heavy menstrual bleeding (period) and, following blood tests, the cause is still unknown, an ultrasound examination of your womb may be used.

A trans-vaginal scan is sometimes used to diagnose fibroids. It involves a small scanner being inserted into your vagina to take a close-up image of your womb.

Fibroids near your inner lining, and those within the cavity of your womb, can be seen directly using a hysteroscope (small telescope used to examine the inside of your womb). To look at the size and shape of the outside of your womb a laparoscope (small flexible tubing used to look inside the abdomen) is used. Both procedures can also be used to take a biopsy (sample of tissue) of the lining or outer layer of your womb.

If an ultrasound scan does not reveal any obvious problems, or if it has identified a problem, such as fibroids, your GP may refer you to a gynaecologist (a specialist in the female reproductive system). If further investigations are required, a biopsy may be carried out. The small sample of your womb lining can then be examined under a microscope.

If you do not have any symptoms from your fibroids, treatment may not be necessary. Some women with minor symptoms, such as heavy periods, choose not to have treatment as their day-to-day life is not affected. After the menopause, fibroids often shrink, and your symptoms will either disappear or ease slightly.

To treat fibroids, your GP may recommend medication. However, in more severe cases, surgery can be considered.

Treatment with medication

The most effective medication to treat fibroids is an injected hormone medicine called gonadotropin releasing hormone agonist (GnRHa). This causes your body to release a very low amount of oestrogen, causing your fibroids to shrink. GnRHa works by preventing your menstrual cycle (period), but it is not a form of contraceptive. However, it does not affect your chances of becoming pregnant after you stop using it.

If you are prescribed GnRHa, it can help ease your heavy periods and any pressure felt on your abdomen. Common side effects include menopause-like symptoms, such as hot flushes, increased sweating, and vaginal dryness. Osteoporosis (thinning of the bones) is a less common side effect. GnRHa is not prescribed for long term use, and is often used to shrink fibroids prior to surgery.

A combination of GnRHa and low doses of Hormone Replacement Therapy (HRT) can be used to shrink your fibroids, whilst preventing the side effects of the menopause. See your GP to discuss the most suitable course of treatment for you.

Other medicines can be used to treat heavy periods, but they are less effective the larger your fibroids are. These include:

• Tranexamic acid these tablets are taken from the start of your period for up to four days. However, treatment should be stopped if your symptoms have not improved within three months. The tablets work by helping the blood in your womb to clot, which reduces the amount of bleeding. Tranexamic acid tablets are not a form of contraception and will not affect your chances of becoming pregnant once you stop taking them.
• Anti-inflammatory medicines such as ibuprofen and mefanamic acid help to ease your periods and are taken for a few days during your period. They work by reducing your body's production of a hormone-like substance, called prostaglandin, which is linked to heavy periods. They are also painkillers but are not a form of contraceptive. Common side effects include indigestion and diarrhoea.
• The contraceptive pill is often taken, during your period, to prevent your menstrual cycle (period) from occurring. Some contraceptive pills also help to reduce any period pain you may experience. See your GP to discuss which contraceptive pill you should use.
• Levonorgestrel intrauterine system (LNG-IUS) is a small plastic device that is placed in your womb and slowly releases the progestogen hormone called levonorgestrel. It prevents the lining of your womb from growing quickly so your bleeding becomes lighter. Possible side effects of LNG-IUS include; having irregular bleeding that may last for more than six months, acne (inflamed skin on the face), headaches, and breast tenderness. It may also stop you having periods at all, although this is rare.

Surgical procedures

Surgical procedures, for treating fibroids, are usually only considered if all other medications are ineffective. There are a number of different surgical procedures that can be carried out to treat fibroids. Your GP will refer you to a specialist who can discuss all the options with you, including the benefits and any associated risks.

Common surgical procedures that are used to treat fibroids include:

• Hysterectomy involves surgery to remove the womb. A hysterectomy is not usually necessary unless the fibroids are very large or you have severe bleeding. A hysterectomy may be advised in order to prevent fibroids recurring. Having a hysterectomy can lead to early menopause and some women experience problems with a reduced libido.
• Myomectomy involves surgery to remove the fibroids from the wall of your womb. A myomectomy is an alternative to having a hysterectomy, particularly for women still wishing to have children. However, the procedure may not always be possible as it depends on your individual circumstances, such as the size, number and position of your fibroids.
• Endometrial ablation is removal of the womb lining. It is usually only carried out if your fibroids are near the inner surface of your womb. The affected womb lining is removed, which may be done in a number of ways, including using laser energy, a heated wire loop, microwave heating, or hot fluid in a balloon. Endometrial ablation can be used as an alternative to a hysterectomy.
• Uterine artery embolisation (UAE) is a new treatment used to block the blood supply to fibroids. This is done by injecting a chemical through a small tube (catheter) that has been guided by X-ray scans into a blood vessel in your leg. This is usually used in women with large fibroids, and has been known to shrink fibroids by up to 60%. As UAE is a new procedure it may not currently be available in certain hospitals, so you should check with your specialist.

Magnetic resonance-guided percutaneous laser ablation

Another new treatment for fibroids is magnetic resonance-guided percutaneous laser ablation. In this procedure, a Magnetic Resonance Imaging (MRI) scan (that uses a strong magnetic field and radio waves to produce detailed pictures of the inside of your body) is used to find your fibroids.

Once the fibroids have been located, fine needles are inserted through your skin and guided into the fibroids. A fibre optic cable (a cable that can transmit beams of light) is threaded through the needles. Light is then targeted at the fibroids, and the heat from the light is used to shrink them.

Magnetic resonance-guided focused ultrasound surgery

Magnetic resonance-guided focused ultrasound surgery is a similar procedure to magnetic resonance-guided percutaneous laser ablation. An MRI scan is used to locate your fibroids and, once they have been found, sound waves are targeted at them. The sound waves produce pulses of energy to shrink your fibroids.

Both magnetic resonance-guided percutaneous laser ablation and magnetic resonance-guided focused ultrasound surgery, are treatments that have been approved by the National Institute of Clinical Excellence (NICE). However, there is still some uncertainty as to the benefits and risks of both treatments. Therefore, if you are considering having either type of treatment, you should discuss the benefits and risks with your doctor.

The majority of women do not experience any problems as a result of their fibroids but, in some cases, they can pose significant complications. This is usually due to the large size and position of the fibroids. Possible complications include:

• Heavy periods (menorrhagia) this does not necessarily mean that there is anything seriously wrong, but it can disrupt your everyday life and make you feel miserable. In some cases, menorrhagia can lead to anaemia, causing fatigue and breathlessness. See the separate health encyclopaedia topic for further information about heavy periods.
• Abdominal pains you may experience discomfort or bloating (swelling) to your lower abdomen, particularly if your fibroids are large. You may also find you need to urinate frequently if your fibroids are pressing on your bladder. This pressure may also mean you have painful bowel movements or feel constipated.
• Miscarriage and premature birth during pregnancy the levels of oestrogen in a woman's body can increase by as much as five times. Because fibroids are thought to be produced by high levels of oestrogen this may lead to complications with the development of the baby, or cause pain and discomfort. In rare cases, fibroids could block the passage of the birth canal causing possible complications during labour.
• Infertility is more common in women with large fibroids as they can interfere with the fertilised egg attaching to the lining of your womb. If you have a submucosal type of fibroid (growing outside the wall of your womb) this could also affect the shape of your womb, making it harder for you to conceive (get pregnant).

Very rarely, in around one in 1,000 cases, a cancer called leiomyosarcoma may begin to develop in the fibroids. Research is still on-going to determine whether these cancerous cells are actually a different form of tumour (an abnormal mass of tissue growth) growing in isolation from the fibroids.