Why Are My Periods So Heavy? When to Investigate Fibroids

Heavy Periods: More Than Just an Inconvenience

Heavy menstrual bleeding, known medically as menorrhagia, is one of the most common gynaecological complaints in the United Kingdom. It affects approximately one in four women at some point in their lives and is the single most common reason for referral to a gynaecologist. While heavy periods can have many causes, uterine fibroids are one of the most frequent — and most treatable — explanations.

If you are experiencing heavy periods, it is important to understand that this is a medical condition, not simply something you must accept. For detailed information about fibroid symptoms, visit our symptoms page.

What Counts as Heavy Periods?

It can be difficult to know whether your periods are genuinely heavy or within the normal range, particularly if you have always experienced heavy bleeding. Clinically, menorrhagia is defined as blood loss of more than 80 millilitres per cycle, but this is not something most women can measure. More practical indicators include:

• Needing to change your pad or tampon every one to two hours
• Passing blood clots larger than a 10 pence coin
• Bleeding through your clothes or bedding despite using protection
• Needing to use double protection (a pad and a tampon simultaneously)
• Periods lasting longer than seven days
• Having to plan your life around your periods, avoiding activities or work
• Feeling excessively tired, breathless, or dizzy (symptoms of anaemia)

If any of these apply to you, your bleeding is likely heavier than normal and warrants investigation.

Why Do Fibroids Cause Heavy Bleeding?

Fibroids cause heavy menstrual bleeding through several mechanisms:

• Increased uterine surface area — fibroids enlarge the uterus, which increases the surface area of the endometrium (uterine lining) that sheds during each period
• Disruption of normal uterine contractions — the uterus contracts during menstruation to help expel the lining. Fibroids can interfere with these contractions, allowing the blood vessels in the uterine wall to bleed for longer
• Distortion of the uterine cavity — submucosal fibroids in particular can stretch and distort the uterine lining, increasing blood loss
• Increased blood supply — fibroids develop their own blood supply, and the increased vascularity of the uterus can contribute to heavier bleeding

Other Causes of Heavy Periods

While fibroids are a common cause, heavy periods can also be caused by other conditions, including:

• Adenomyosis — a condition where tissue similar to the uterine lining grows into the muscular wall of the uterus
• Endometrial polyps — small, usually benign growths on the uterine lining
• Hormonal imbalances — particularly around the menopause or in polycystic ovary syndrome (PCOS)
• Clotting disorders — conditions affecting the blood's ability to clot properly
• Intrauterine devices (coils) — copper IUDs can increase menstrual bleeding

A proper assessment by a specialist can help determine the cause and guide treatment.

When Should You Seek Help?

You should consult a healthcare professional about your periods if:

• Your periods are significantly impacting your daily life, work, or relationships
• You are experiencing symptoms of anaemia (tiredness, breathlessness, pale skin, dizziness)
• Your periods have become heavier over time
• You have persistent pelvic pain alongside heavy bleeding
• You have a family history of fibroids

What Happens at a Specialist Assessment?

At the North London Fibroid Clinic, a specialist assessment typically includes a detailed discussion of your symptoms and medical history, a pelvic examination, blood tests to check for anaemia, and imaging such as an ultrasound or MRI scan to identify any fibroids or other structural abnormalities. This allows us to make an accurate diagnosis and discuss the full range of treatment options with you.

If heavy periods are affecting your quality of life, do not suffer in silence. Book a consultation with our specialist team to find out what is causing your symptoms and explore the treatment options available to you.