Uterine Fibroids: Heavy Periods, Pelvic Pressure, and Treatment Options

Introduction

Uterine fibroids are among the most common gynaecological conditions — affecting up to 70% of women by the age of 50, though most will never know they have them. When fibroids do cause problems, the effects can be significant: heavy periods leading to anaemia, pelvic pressure and discomfort, and in some cases effects on fertility or pregnancy.

Despite their prevalence, fibroids are poorly understood by many people experiencing them. This guide explains what fibroids are, why they cause the symptoms they do, how they are investigated, and what treatment options are available — including doing nothing when that is the right choice.

Key Points

Uterine fibroids are non-cancerous growths of muscle and fibrous tissue in or around the uterus; they are very common
Many fibroids cause no symptoms and require no treatment
Heavy or prolonged periods are the most common symptom and can lead to iron deficiency anaemia
Pelvic pressure, frequent urination, constipation, and pelvic pain are other common effects
Fibroids do not always affect fertility or pregnancy, but location and size matter
Fibroids tend to shrink after menopause; any postmenopausal bleeding should always be assessed
Treatment options range from watchful waiting to medical and surgical approaches; the right choice depends on symptoms, size, location, fertility plans, and personal preferences
Seek urgent help for very heavy bleeding, fainting, severe pain, fever, postmenopausal bleeding, or signs of severe anaemia

What Are Uterine Fibroids?

Uterine fibroids — also called leiomyomas or myomas — are benign (non-cancerous) growths made up of smooth muscle and fibrous connective tissue. They develop within or around the wall of the uterus (womb). Fibroids vary enormously in size: from a few millimetres to several centimetres, and occasionally larger. A person may have one fibroid or many.

Are fibroids dangerous? Fibroids are almost always benign. A rare uterine cancer called leiomyosarcoma can look similar on imaging, but this is uncommon and is not related to the usual progression of fibroids. If new, rapidly growing, or unusual features are present, clinical assessment is warranted — but routine fibroids do not become cancer.

Where Fibroids Grow

The location of a fibroid within or around the uterus affects what symptoms it causes:

Intramural — within the muscular wall of the uterus; the most common type
Submucosal — projecting into the uterine cavity; most likely to cause heavy bleeding and fertility problems
Subserosal — projecting outward from the outer surface of the uterus; more likely to cause pressure, bulk symptoms, or urinary problems
Pedunculated — attached by a stalk, either inside the uterine cavity or on the outer surface

How Common Are Fibroids?

Fibroids are one of the most frequently occurring conditions of the female reproductive system. Studies using imaging suggest that up to 70% of women will have at least one fibroid by the age of 50, but many will never know because symptoms are absent. Those who seek care typically do so because of heavy periods, pelvic pressure, or problems identified during investigation of another symptom.

Why Do Fibroids Develop?

The exact cause of fibroids is not fully understood, but several factors are associated with their development:

Hormones — oestrogen and progesterone promote fibroid growth; fibroids often grow during the reproductive years and tend to shrink after menopause when hormone levels fall
Genetics — fibroids run in families; having a first-degree relative with fibroids increases your likelihood of developing them
Age — fibroids are most common during the reproductive years, particularly from the 30s onward
Pregnancy hormones — elevated oestrogen and progesterone during pregnancy can cause fibroids to grow, though they often return to a similar or smaller size after delivery

Fibroids are not caused by lifestyle choices. They are not preventable in the usual sense.

Common Symptoms

Many people with fibroids have no symptoms at all. When symptoms do occur, they depend on the fibroid’s location, size, and number.

Menstrual Changes

Heavy periods (menorrhagia) — the most common symptom; periods may be significantly heavier than usual, requiring frequent pad or tampon changes, or passing large clots
Prolonged periods — periods lasting longer than 7 days
Bleeding between periods — less common but can occur, particularly with submucosal fibroids

Pelvic Pressure and Pain

Pelvic pressure or fullness — a sensation of heaviness or pressure in the lower abdomen
Pelvic or lower back pain — aching or discomfort, sometimes worsening during periods
Pain during sex — depending on fibroid location

Bladder and Bowel Effects

Frequent urination or urgency — fibroids pressing on the bladder
Constipation or bloating — fibroids pressing on the bowel

Other Symptoms

Abdominal bloating or a visibly enlarged lower abdomen — with larger fibroids
Fatigue — often related to heavy periods and resulting iron deficiency

Heavy Bleeding and Anaemia

Heavy menstrual bleeding is the most significant symptom for many people with fibroids — and its consequences extend well beyond inconvenience. Recurring blood loss depletes iron stores, leading to iron deficiency anaemia.

Symptoms of iron deficiency or anaemia include:

Persistent fatigue and low energy
Dizziness or lightheadedness
Breathlessness on exertion
Palpitations (awareness of the heartbeat)
Difficulty concentrating
Feeling cold

Iron deficiency can develop slowly, and many people have lived with it for months or years without realising it is causing their symptoms. Blood tests — a full blood count and ferritin — are an important part of assessing anyone with heavy periods, as a normal haemoglobin does not exclude iron depletion.

If iron deficiency or anaemia is confirmed, iron replacement may be recommended. Treating the underlying cause of heavy bleeding is an essential part of restoring iron levels long-term.

For more on fatigue and its causes, see Why Am I Always Tired?. For more on heavy periods and their investigation, see Heavy Periods: When to Seek Help.

Fibroids and Fertility

Most people with fibroids can become pregnant without difficulty, and many pregnancies occur with fibroids present and cause no problems at all.

However, fibroid location matters:

Submucosal fibroids (projecting into the uterine cavity) are most likely to affect fertility — they can interfere with implantation or increase the risk of early miscarriage
Intramural fibroids may affect fertility in some circumstances, depending on size and proximity to the uterine cavity
Subserosal fibroids generally have less impact on fertility

If you are trying to conceive and have known fibroids, specialist review is advisable to assess whether the fibroid location or size is likely to be relevant. Treatment — particularly myomectomy (surgical removal of fibroids) — may be considered in selected cases, but this decision requires careful individual assessment.

Fibroids and fertility is a nuanced area. Decisions should be made collaboratively with a gynaecologist or fertility specialist who can review the specifics of your situation.

Fibroids and Pregnancy

Many pregnancies with fibroids progress entirely normally. However, fibroids may occasionally be associated with:

Pelvic pain during pregnancy, particularly if a fibroid undergoes degeneration (a process called red or carneous degeneration, often in the second trimester)
Increased risk of miscarriage in some circumstances
Placental complications depending on fibroid location
Preterm birth in some cases
Breech presentation or other malpresentation at term
Increased likelihood of caesarean birth, particularly with large or poorly positioned fibroids

Most of these complications are uncommon. If you are pregnant and have fibroids, your obstetric team will monitor your pregnancy accordingly. Anxiety about fibroids and pregnancy is understandable, but most outcomes are good.

Do not make decisions about pregnancy management based on fibroid concern alone — this is a conversation for your care team.

Fibroids and Menopause

Fibroids are driven by oestrogen and progesterone. After menopause, as hormone levels fall, fibroids typically shrink and symptoms often resolve without treatment. This is why watchful waiting is a reasonable option for people approaching menopause who have manageable symptoms.

Any vaginal bleeding after menopause requires medical assessment, regardless of a previous fibroid diagnosis. Postmenopausal bleeding is not normal and must be investigated to exclude endometrial cancer and other causes — it should not be assumed to be fibroid-related without evaluation.

See Menopause: Symptoms, Stages, and What to Expect for more on the menopausal transition.

Diagnosis

Clinical Assessment

A thorough symptom history — including menstrual pattern, pain, pressure symptoms, and the impact on daily life — is the starting point. A pelvic examination may detect an enlarged or irregular uterus.

Blood Tests

Full blood count and iron studies (ferritin) — to assess for anaemia and iron deficiency
Pregnancy test — where relevant
Thyroid function (TSH) — thyroid disease can cause heavy or irregular periods and fatigue; testing may be appropriate if these symptoms are prominent (see Thyroid Disease: Symptoms, Tests, and Treatment)

Pelvic Ultrasound

Ultrasound is the standard first-line imaging test for fibroids. It can confirm the presence of fibroids, their number, size, and location — and help guide treatment decisions. Transvaginal ultrasound (TVS) provides more detailed images than transabdominal ultrasound in most cases.

MRI

MRI provides more detailed information about fibroid type and location and is used when surgical planning is needed, or when the ultrasound findings are complex.

Hysteroscopy or Sonohysterography

These investigations allow direct visualisation or detailed imaging of the uterine cavity. They are particularly useful for identifying submucosal fibroids (those projecting into the cavity) that may not be fully characterised on standard ultrasound.

Differential Diagnosis

Other conditions can cause similar symptoms and must be considered:

Endometriosis — pelvic pain and heavy periods; often coexists with fibroids
Adenomyosis — endometrial tissue within the uterine wall; causes heavy periods and an enlarged, tender uterus; often misidentified as fibroids
Endometrial polyps — benign growths of the uterine lining causing irregular bleeding
PCOS — irregular or heavy periods from anovulatory cycles
Thyroid disease — hypothyroidism causes heavier, more frequent periods
Pregnancy-related bleeding — must be excluded when relevant
Pelvic infection — can cause pain and bleeding
Endometrial hyperplasia or cancer — must be considered in women over 40 with new, worsening, or postmenopausal bleeding

Treatment Options

Treatment depends on symptoms, fibroid size and location, fertility goals, proximity to menopause, and personal preferences. Not all fibroids need treatment.

Watchful Waiting

For fibroids that are small, stable, and not causing significant symptoms, monitoring without active treatment is a reasonable and commonly recommended approach. Regular review — including symptoms and sometimes repeat imaging — allows treatment to be considered if things change.

Treating Associated Anaemia

If heavy bleeding has caused iron deficiency anaemia, iron replacement (if prescribed) is an important part of care. Treating the bleeding itself is also necessary to prevent anaemia from recurring.

Medicines for Symptom Control

Tranexamic acid — reduces heavy menstrual blood loss by reducing clot breakdown. Taken during periods only. Does not affect hormones or fertility.

NSAIDs (anti-inflammatory medicines) — reduce blood loss and relieve period pain. Taken during menstruation.

Hormonal intrauterine system (LNG-IUS / Mirena) — releases progestogen locally into the uterine cavity. Very effective for heavy bleeding and is often a first-line option for women wanting to preserve fertility or avoid surgery. Most effective for smaller fibroids that do not significantly distort the cavity.

Combined hormonal contraception (combined pill, patch, ring) — regulates cycles and reduces blood loss. General contraceptive cautions apply.

Progestogen therapy — oral or injectable progestogens can reduce bleeding in some women.

GnRH analogues and antagonists — these medicines substantially reduce oestrogen levels, causing fibroids to shrink and periods to stop or become very light. They are effective but are typically used for a limited time (before surgery, or in specific circumstances) because of effects on bone density and menopausal-type side effects. GnRH antagonists (such as relugolix or elagolix) are newer options that may be used with add-back hormone therapy.

Discuss specific medicine suitability, contraindications, and side effects with your clinician. See Medication Safety: How to Avoid Common Medicine Problems for general guidance on medicines.

Minimally Invasive and Surgical Options

Uterine artery embolisation (UAE) — a radiological procedure that blocks the blood supply to fibroids, causing them to shrink. It preserves the uterus and is performed through a small incision in the groin. Recovery is typically shorter than open surgery.

Myomectomy — surgical removal of fibroids while preserving the uterus. Options include hysteroscopic myomectomy (for submucosal fibroids, performed through the vagina), laparoscopic myomectomy, or open (abdominal) myomectomy. Appropriate for women who want to preserve fertility or avoid hysterectomy.

Focused ultrasound (MRgFUS) — uses focused ultrasound waves to destroy fibroid tissue without an incision. Availability is limited; not suitable for all fibroid types or locations.

Endometrial ablation — destroys the uterine lining to reduce or stop periods. Effective for heavy bleeding but is not appropriate if fibroids are the primary cause or if there are large fibroids; not suitable for women wanting future pregnancy.

Hysterectomy — surgical removal of the uterus; the only treatment that permanently ends fibroid symptoms and prevents recurrence. Used when other treatments have failed or are not appropriate, or when the person has completed childbearing and wishes a definitive solution.

Treatment choice is not one-size-fits-all. Fibroid type, location, and size; severity of symptoms; desire for future pregnancy; proximity to menopause; and personal values all shape the decision.

Questions to Ask Before Starting Treatment

These questions can help guide a meaningful conversation with your clinician:

What type and location are my fibroids — and are they likely to be causing my symptoms?
Do I have anaemia? Do I need iron replacement?
What are my fertility goals, and how do they affect the choice of treatment?
What non-surgical options are available for my situation?
If surgery is recommended, what are the risks, recovery time, and recurrence rates?
What follow-up or monitoring will I need?
If I choose watchful waiting, what would prompt a change in approach?

When to Seek Urgent Help

Seek emergency or urgent medical attention if you experience:

Very heavy bleeding — soaking through pads or tampons rapidly, or passing large blood clots
Dizziness, fainting, or collapse — suggesting significant blood loss or severe anaemia
Severe pelvic or abdominal pain — particularly if sudden or different from usual
Fever with pelvic pain — may suggest infection
Bleeding during pregnancy or sudden worsening pain in a known pregnancy with fibroids
Postmenopausal bleeding — any vaginal bleeding after menopause requires urgent assessment to exclude endometrial cancer
Chest pain, severe breathlessness at rest, or collapse — may indicate severe anaemia or another emergency

If you are uncertain whether your symptoms need urgent attention, seek medical assessment promptly rather than waiting.

FAQ

What are uterine fibroids? Uterine fibroids are non-cancerous growths of muscle and fibrous tissue that develop in or around the uterus. They are common and do not always cause symptoms.

Are fibroids cancer? Fibroids are usually benign and are not cancer. Rare cancers can arise in the uterus, but most fibroids are non-cancerous. New, rapidly changing, or unusual symptoms should always be assessed by a clinician.

What symptoms can fibroids cause? Fibroids can cause heavy or prolonged periods, pelvic pressure or bloating, pelvic or lower back pain, frequent urination, constipation, pain during sex, and in some cases fertility or pregnancy complications.

Do all fibroids need treatment? No. Fibroids that are small, stable, and not causing symptoms may only need monitoring. Treatment depends on symptoms, fibroid size and location, age, fertility goals, and overall health.

When should I seek urgent help for fibroid symptoms? Seek urgent help for very heavy bleeding, fainting or dizziness, severe pelvic pain, fever, bleeding in pregnancy, postmenopausal bleeding, or symptoms of severe anaemia such as chest pain, breathlessness, or collapse.