Uterine fibroids—also known as leiomyomas or myomas—are benign (non-cancerous) growths that develop within or around the muscular wall of the womb (uterus). They are extremely common, affecting up to 70% of women by the age of 50.
While many women are unaware they have fibroids, for others, they can cause significant symptoms such as heavy menstrual bleeding, pelvic pain, bloating, or even fertility issues.
In this guide, we explore seven key facts about fibroids, including what causes fibroids, whether fibroids cause bleeding, which size of fibroid is dangerous, the full range of fibroids treatment options (including new treatments for fibroid surgery), and why a private ultrasound scan can be an important first step in diagnosis.
What Are Fibroids?
Fibroids are made up of muscle and fibrous tissue. They can vary greatly in size—from as small as a pea to as large as a melon—and are categorised by where they grow:
- Intramural fibroids – grow within the muscular wall of the womb
- Subserosal fibroids – grow outside the womb into the pelvis
- Submucosal fibroids – grow into the cavity of the womb and are most likely to cause heavy bleeding
Quick fact: Fibroids are not cancerous and rarely develop into cancer. However, they can still significantly affect quality of life if they cause symptoms.
What Causes Fibroids?
The exact cause of fibroids is not fully understood, but research suggests several contributing factors:
- Hormonal influence – Oestrogen and progesterone promote the growth of fibroids
- Genetic factors – A family history of fibroids increases your risk
- Lifestyle factors – Obesity, vitamin D deficiency, and diet may play a role
Many studies have shown that fibroids tend to shrink after menopause when hormone levels drop.
Can Fibroids Cause Bleeding? / Do Fibroids Cause Bleeding?
Yes. Certain types of fibroids—especially submucosal fibroids—can cause heavy menstrual bleeding (menorrhagia), prolonged periods, or bleeding between periods.
In fact, fibroids are a leading cause of abnormally heavy periods in women of reproductive age.
Excessive bleeding can lead to anaemia, fatigue, and reduced quality of life. If you experience unusually heavy or prolonged bleeding, it is important to seek medical assessment promptly.
How Do You Know if You Have Fibroids?
Fibroids can sometimes be “silent” and cause no symptoms at all, meaning many people only discover them during a routine scan.
However, when symptoms do occur, they can vary depending on the size, number, and location of the fibroids.
Common signs and symptoms include:
- Heavy or prolonged menstrual bleeding
- Pelvic pain or pressure
- Bloating or swelling in the lower abdomen
- Frequent urination (if fibroids press on the bladder)
- Pain during intercourse
- Lower back pain
- Constipation (if fibroids press on the bowel)
These symptoms can also be linked to other conditions, so it’s important not to self-diagnose.
The only way to confirm fibroids is through a diagnostic test — most commonly, an ultrasound scan, which nowadays can be booked privately without a GP referral.
If you’re experiencing any of the symptoms above, booking a scan can give you clarity and help you make informed decisions about your health.
Which Size of Fibroid Is Dangerous?
There is no strict size at which a fibroid becomes “dangerous,” but larger fibroids (often defined as ≥5 cm in diameter) are more likely to:
- Cause bulk symptoms such as pelvic pressure, urinary frequency, or constipation
- Affect fertility or pregnancy outcomes
- Require surgical or interventional treatment
Rapidly growing fibroids should always be assessed, as, although rare, they can mimic more serious conditions.
How to Detect Fibroids
How to Detect Fibroids
The most reliable and widely used method to detect fibroids is ultrasound scanning.
During an ultrasound, high-frequency sound waves are used to create detailed images of the uterus. This allows a healthcare professional to:
- Identify fibroids – pinpointing their size, number, and location (e.g., inside the uterine wall, on the surface, or within the cavity).
- Differentiate from other conditions – such as ovarian cysts or polyps.
- Monitor changes over time – useful if your fibroids are being observed rather than immediately treated.
There are two main types of ultrasound for detecting fibroids:
- Transabdominal Ultrasound – the probe is placed on your abdomen; useful for viewing larger fibroids and giving an overview of the pelvic area.
- Transvaginal Ultrasound – the probe is gently inserted into the vagina; it provides closer, more detailed images of the uterus, especially for smaller fibroids.
At The Scan Clinic, our private pelvic ultrasound scans offer same-day appointments, high-resolution imaging, and fast results — so you can get clarity about your symptoms quickly and comfortably.
Fibroid Treatments: From Conservative to Surgical
The best treatment for fibroids depends on factors such as size, location, symptoms, and whether you wish to preserve fertility.
Non-Surgical Options
- Watchful waiting – For small, symptom-free fibroids
- Medications – Such as hormonal contraception or Gonadotropin-releasing hormone (GnRH) analogues to shrink fibroids
- Tranexamic acid – To reduce heavy menstrual bleeding
Surgical & Minimally Invasive Options
- Myomectomy – Surgical removal of fibroids, preserving the uterus
- Hysterectomy – Removal of the uterus (for severe or recurrent fibroids)
- Uterine artery embolisation (UAE) – Blocks blood flow to fibroids, causing them to shrink.
New Treatments for Fibroid Surgery
Medical innovation continues to improve outcomes for women with fibroids:
- MRI-guided focused ultrasound surgery (MRgFUS) – Uses high-intensity ultrasound waves to destroy fibroid tissue without incisions
- Laparoscopic & robotic-assisted myomectomy – Minimally invasive techniques with faster recovery
- Radiofrequency ablation – Uses heat to shrink fibroids
While these options are not available everywhere, some specialist centres in the UK now offer them—speak to your healthcare provider for referral options.
Private Ultrasound Scans for Fibroid Assessment
A pelvic ultrasound scan is one of the most effective and widely used tools for diagnosing fibroids.
At The Scan Clinic, our private ultrasound scans offer:
- Fast appointments—often available within days
- Detailed imaging and measurement of fibroids
- A comprehensive report to share with your GP or specialist
Tip: See our Pelvic Ultrasound Scan page for more details on how the scan works, preparation, and pricing.
When to See a Doctor
Seek medical advice if you have:
- Heavy or prolonged menstrual bleeding
- Pelvic pain or pressure
- Difficulty conceiving
- Rapidly increasing abdominal size
You can also visit the NHS fibroids page for more information.
Book Your Private Fibroid Ultrasound Scan Today
Don’t wait for answers. A private pelvic ultrasound can give you the clarity you need—fast.
Book your appointment now or call our friendly London team to discuss your concerns.
Fibroid FAQ’s
Can fibroids cause bleeding?
Yes. Fibroids—especially submucosal types—can cause heavy or irregular bleeding.
Which size of fibroid is dangerous?
Large fibroids (≥5 cm) or rapidly growing fibroids may require closer monitoring or treatment.
What is the best treatment for fibroids?
This depends on your symptoms, the size and location of fibroids, and your fertility goals.
Are there new treatments for fibroid surgery?
Yes—options like MRgFUS and robotic-assisted myomectomy offer minimally invasive alternatives.
How soon can I get a private ultrasound scan?
At The Scan Clinic, appointments are often available within days. Book your scan here.
How to detect fibroids?
Fibroids are most reliably detected with an ultrasound scan, which can show their size, number, and location. At The Scan Clinic, we offer high-resolution pelvic ultrasounds for fast and accurate diagnosis.
How do you know if you have fibroids?
Common signs include heavy periods, pelvic pain, bloating, and frequent urination. The only way to confirm is with an ultrasound scan, available privately at The Scan Clinic with same-day results.
How much does a fibroid scan cost?
In the UK, the cost of a fibroid scan can range from £130 to over £400, depending on the provider and whether additional tests are included. At The Scan Clinic, our private gynaecological ultrasound scans are affordable, provide quick results, and start from just £145.
