Fibroids fact sheet

What are fibroids?

Fibroids are noncancerous growths found in the muscle wall of the uterus. They can grow on the outer wall of the muscle (subserosal), within the muscle wall (intramural), on the inner wall lining the cavity of the uterus (submucosal), or a combination of these.

Fibroids can vary in size from a pea to a rockmelon or bigger.

This condition occurs in up to 70% of women aged under 50. After menopause, fibroids usually shrink and may disappear.

The below picture shows a uterus with different types of fibroids.

Symptoms

About 20% to 30% of women experience symptoms related to fibroids.

For example:

• heavy or long periods
• painful periods
• bleeding in between periods – this depends on the size and position of the fibroids
• iron deficiency, due to heavy periods – this might make you feel tired or dizzy.

Other symptoms include:

• painful sex
• feeling heaviness or pressure in your back, bowel or bladder
• feeling like you haven’t emptied your bowel or bladder
• weeing a lot
• swelling in your lower abdomen
• pregnancy complications.

Causes

We don’t know exactly what causes fibroids, but we do know the female hormones oestrogen and progesterone stimulate the growth of fibroids.

Some factors may increase the risk of fibroids.

For example:

• a family history of fibroids
• starting your periods early
• polycystic ovary syndrome (PCOS)
• obesity
• high blood pressure.

Diagnosis

Fibroids can be diagnosed in different ways.

For example:

• an ultrasound on your abdomen or inside your vagina
• an MRI scan
• hysteroscopy – a thin telescope shows the inside of your uterus (this is performed with or without a local anaesthetic)
• laparoscopy – a thin telescope goes into your belly button to see your pelvic organs (this is performed under general anaesthetic).

Fertility and pregnancy

Fibroids can affect fertility, depending on their size and location. Fibroids may also cause miscarriage or early labour. In some cases, caesarean section may be recommended for future births.

Treatment and management

Most fibroids don’t require treatment unless you are planning to get pregnant, or symptoms such as period pain and heavy bleeding stop you from doing things you normally do.

If fibroids don’t affect your daily life, you can choose to leave them untreated and simply increase iron and vitamin C in your diet.

Treatment will depend on your symptoms and the size, number and location of your fibroids.

There are different treatments for fibroids, including:

• medical – for example, mefenamic acid, tranexamic acid or hormonal treatments such as the Mirena® IUD or combined oral contraceptive pill
• radiological – uterine artery embolisation (a non-surgical procedure that blocks blood supply to part of the uterus) or high-intensity ultrasound, guided by MRI
• surgery – myomectomy (performed as a hysteroscopy or laparoscopy, depending on the location of fibroids) or a hysterectomy (removal of the uterus).

Talk to your doctor or specialist about the benefits and risks of each option before you decide.

When to see your doctor

See your doctor straight away if you experience symptoms such as a sudden change to your bleeding, very heavy periods or unexplained weight loss.

For more information, resources and references, visit the Jean Hailes ovaries and uterus web page.