25 Mar, 2024

MRI Scan for Fibroids: How Are Fibroids Diagnosed in the Uterus?

If you’re experiencing symptoms associated with fibroids, such as bloating, pain or heavy periods, or if you know you have fibroids and are wondering what the next steps are, we have the information you need. Our guide will walk you through the symptoms, diagnosis and treatment for fibroids and let you know what to expect.

What are fibroids?

Fibroids (uterine myomas or leiomyomas) are non-cancerous (benign) growths that develop around or within the womb (uterus), usually during the fertile years when you can get pregnant and give birth. Around 2 in 3 women develop at least one fibroid at some point during their lives, and they’re most common between the ages of 30 and 50. Black and Asian women have a higher risk of developing fibroids than white women. 

Fibroids are a mix of fibrous tissue and muscle and can vary in size, from being almost microscopic to the size of a melon or a grapefruit. Many people have them but don’t realise because they don’t always cause symptoms. 

What are the different fibroid locations?

Experts divide fibroids into three main types, depending on where they grow:

  • Intramural fibroids are the most common type and grow within the muscle wall of the womb.

  • Subserosal fibroids grow on the outer side of the womb wall and can extend further into the pelvis.

  • Submucosal fibroids grow under the womb's inner lining (endometrium) and can extend into the uterus. 

Fibroids can sometimes grow in other areas, such as the ligaments holding the womb or the fallopian tube, but this is less common.

How quickly do fibroids grow?

How quickly fibroids grow can depend on many factors, such as age, where they’re growing, or whether or not you’re pregnant. Experts who have tried to measure an average growth rate say that fibroids can increase by around 9% every six months, but they can also grow or shrink seemingly spontaneously and at lower or higher rates than this. 

What are the symptoms of fibroids?

While many people with fibroids never experience any symptoms at all, symptoms can include:

  • heavy and painful periods (dysmenorrhoea)

  • pelvic pain, pressure, or discomfort

  • pain or difficulty during sex (dyspareunia)

  • abdominal pain or bloating

  • back pain

  • urinary tract infections or other urinary problems

  • constipation or pain during bowel movements

  • problems with fertility

Can fibroids cause weight gain?

It’s possible. Lots of fibroids can cause the womb to enlarge, which may lead to weight gain. However, there is more evidence to suggest that weight gain causes a higher risk of fibroids. People who are overweight or obese are more likely to develop fibroids and have fibroids that grow faster than people of normal weight. 

Can fibroids cause bloating (Fibroid Belly)?

Yes, fibroids and bloating often go hand-in-hand. Fibroids can add pressure to your gastrointestinal tract, causing bloating (‘fibroid belly’) and other abdominal discomfort, such as cramping, constipation, back pain, and urinary problems. They can also cause pelvic pressure or nudge into other organs, which can cause symptoms similar to bloating. 

What do fibroid blood clots look like?

People with fibroids may notice blood clots during their periods, either due to heavier menstrual bleeding or because they affect blood flow through the womb, causing blood clots. Clots can vary in appearance but may be dark red or brown with a jelly-like consistency.

It’s also possible, though rare, to expel fibroid tissue, which appears as a dark and clotted vaginal discharge.

What does fibroid pain feel like?

Fibroid pain can feel like a range of sensations, from a dragging and heavy feeling in the pelvis to sharp bursts of pain. It can also depend on the size and location of the fibroids -  for example, larger fibroids are more likely to cause pain. While most people don’t have any pain, those who do may describe it as similar to period cramps.

How are fibroids diagnosed?

A clinician or GP will usually perform a pelvic examination if they suspect fibroids. They may also refer you for further tests, such as an ultrasound or MRI scan. If you prefer to skip the waiting lists and go straight to the scan but are unsure which scan is best for you, book a consultation with one of our clinicians. They can give you the advice and information you need, and there’s no obligation to book a scan afterwards.

The following scans can take a closer look at fibroids and give you an idea of whether you need treatment:

Fibroid ultrasound:

A fibroid ultrasound may be abdominal (using a probe on your abdomen) or transvaginal (using a small probe inserted into your vagina).

A fibroid usually appears as a round, well-defined mass during an ultrasound. It may look darker than surrounding tissues and have a mix of textures inside. There may be a shadow at the edges, and sometimes, there’s a shadow that looks like a fan inside. 

MRI scan for fibroids:  

A pelvic MRI for fibroids will also show any growths as well-defined masses. An MRI for fibroids can give detailed images compared to ultrasounds, so you may notice additional features such as fluid-filled spaces, bleeding or calcium deposits. When it comes to fibroids, MRI scans can help to identify different types of fibroids and help your clinician recommend treatment options.

What size of fibroid is considered dangerous?

Bigger fibroids, usually over 10 cm in diameter, can bring more risks and are more likely to cause complications, such as deep vein thrombosis (DVT) or heavy bleeding after giving birth. 

Whether your fibroid is dangerous or not may also depend on whether you are pregnant. Large fibroids can cause pregnancy complications, such as premature birth, having a breech birth or having a caesarean.  

How are fibroids treated?

If you need treatment for your fibroids, there are many options to consider. The right treatment for you depends on your age, whether you want to have children and your symptoms. Your clinician should go through each one with you and let you know the risks and benefits of each. 

Treatments include:

  • Drugs that balance hormones: Can temporarily stop or shrink fibroid growth by affecting levels of oestrogen or progesterone.

  • Surgical removal (myomectomy). Can be done through hysteroscopy (via the vagina) or keyhole surgery (through a small incision in the abdomen). Larger fibroids may need open surgery. Fibroid removal surgery costs in the UK can range from £5,000 to £10,000.

  • Cutting off the blood supply to the fibroid: A radiologist injects a special agent into the blood vessels supplying the fibroid, cutting off its blood supply and shrinking the fibroid.

  • Destroying fibroid tissues: A surgeon will use techniques such as electric currents, lasers, radio waves, or ultrasound to destroy the fibroid.

  • Removing the womb lining: Suitable for smaller fibroids or those that cause heavy bleeding. However, it does mean you’re unlikely to conceive after the procedure.

  • MRI-guided focused ultrasound treatment of uterine fibroids (MRgFUS): A non-invasive procedure that uses high-intensity ultrasound waves to heat and destroy the fibroids.

  • Hormonal contraceptives: Birth control pills or hormone-containing intrauterine devices (IUDs) can help manage symptoms like heavy bleeding and pelvic pain.

  • Nonsteroidal anti-inflammatory drugs (NSAIDs): Medications like ibuprofen can alleviate pain associated with fibroids.

  • Watchful waiting: Monitoring fibroids without treatment if they're not causing significant symptoms.

If you think you may have fibroids, or you know you have fibroids and you want to take the first step towards treatment, book an MRI scan for fibroids to get the answers you need. 


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