Fibroids

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.

This picture shows a uterus with different types of fibroids.

Symptoms

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

For example:

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

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

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.

Medical treatment

Your doctor may recommend different medical treatments, such as mefenamic acid, tranexamic acid or hormonal treatments (e.g. the combined oral contraceptive pill or Mirena® IUD).

Your doctor may recommend a combination of medicines and hormones to shrink your fibroids, usually if infertility is an issue. After you stop treatment, your fibroids can grow back.

Radiological treatment

You may be able to treat your fibroids with radiological treatment.

For example:

• uterine artery embolisation (a non-surgical procedure that blocks blood supply to part of the uterus)
• high-intensity ultrasound, guided by MRI (only suitable for certain types of fibroids).

Surgery

You may need different types of surgery to remove fibroids. The surgery will depend on the size and position of your fibroids.

For example:

• a myomectomy, performed as a hysteroscopy (via the vagina) or laparoscopy (keyhole surgery)
• hysterectomy (removal of the uterus) – if you have large or multiple fibroids.

Talk to your doctor or specialist about the potential 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 (i.e. soaked pads every hour or golf-ball sized blood clots)
• unexplained weight loss or loss of appetite.

Related resources

Download our fibroids fact sheet (PDF 200KB)