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Health condition · Clinically reviewed

Adenomyosis, from heavy periods to a clear plan.

Endometrial tissue inside the uterine muscle - common, under-diagnosed and very treatable. A stepped medical and uterine-sparing approach usually beats jumping to surgery.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, RCOG, ESHRE and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including MRI staging, LNG-IUS, relugolix combination (Ryeqo) and uterine-sparing options.

Key facts

Adenomyosis at a glance.

The essentials, in plain English - what it is, who gets it, how it is diagnosed and the treatment ladder used in the UK today.

  • What it is

    Ectopic endometrial glands and stroma living inside the myometrium - distinct from endometriosis, which grows outside the uterus.

  • How common

    Affects an estimated 20 to 35 percent of women of reproductive age, though it is often undiagnosed for years.

  • Classic presentation

    Heavy menstrual bleeding, painful periods, chronic pelvic pain and a boggy, enlarged, tender uterus.

  • Focal vs diffuse

    Focal adenomyomas behave like discrete lesions; diffuse disease infiltrates the myometrium and drives most symptoms.

  • Diagnosis

    Transvaginal ultrasound is first line - MRI pelvis is the gold standard imaging test. Histology needs a hysterectomy specimen.

  • Fertility impact

    Associated with subfertility and higher miscarriage risk - ultra-long GnRH agonist protocols before IVF can improve outcomes.

Why this guide matters

A stepped plan, not a straight line to hysterectomy.

Adenomyosis is common and often undiagnosed for years. The three points below shape everything else on this page.

  • Imaging changes the conversation

    TVUS and MRI can now diagnose adenomyosis confidently - most women never need a tissue biopsy to start effective treatment.

  • Medical therapy does most of the work

    LNG-IUS, continuous pill, dienogest and Ryeqo control symptoms in the majority - given three to six months to settle.

  • Uterine-sparing options exist

    Embolisation, HIFU and laparoscopic adenomyomectomy preserve the uterus - hysterectomy is definitive but rarely the first step.

How the diagnosis is made

From first symptoms to a clear plan.

The steps a UK GP or gynaecologist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    Symptom and cycle history

    Bleeding volume, dysmenorrhoea, cycle length, dyspareunia and any subfertility - the pattern often points strongly to adenomyosis.

  2. 02

    Assessing

    Bimanual examination

    A globular, boggy, tender and enlarged uterus is the classic clinical finding.

  3. 03

    Assessing

    Baseline bloods

    Full blood count for anaemia from heavy bleeding, ferritin, thyroid function and hormone panel where relevant.

  4. 04

    Confirming

    Transvaginal ultrasound

    Looks for asymmetric myometrial thickening, junctional zone thickening greater than 12 mm, myometrial cysts and a heterogeneous myometrium.

  5. 05

    Confirming

    MRI pelvis

    The gold standard imaging test - defines junctional zone, focal versus diffuse disease and any coexisting fibroids or endometriosis.

  6. 06

    Planning

    Fertility work-up if trying

    AMH, tubal patency and semen analysis where subfertility is part of the picture - the plan changes if IVF is on the horizon.

  7. 07

    Planning

    Specialist gynaecology review

    For staging, uterine-sparing surgical planning or definitive management - especially with focal adenomyomas or coexisting pathology.

Typical timeline: first visit to a confirmed diagnosis and settled plan in weeks, not months.

Symptoms

What adenomyosis actually feels like.

The classic mix of heavy periods, severe cramps, chronic pelvic pain and a boggy uterus - and the features that mean it is time to escalate.

  • Heavy menstrual bleeding

    Prolonged, heavy periods that soak through protection - a leading reason women seek help and a common cause of iron deficiency.

  • Severe dysmenorrhoea

    Cramping period pain that is often crescendo, poorly relieved by simple analgesia and worsening year on year.

  • Chronic pelvic pain

    Non-cyclical pelvic ache between periods - constant, dull and sometimes worse with activity or intercourse.

  • Boggy, enlarged uterus

    A globular, tender, softly enlarged uterus on examination - a hallmark that separates adenomyosis from fibroids.

  • Deep dyspareunia

    Pain with deep penetration - a common but under-reported symptom that improves with hormonal suppression.

  • Subfertility

    Difficulty conceiving and higher miscarriage risk - the junctional zone disruption affects implantation.

  • Iron-deficiency anaemia

    Fatigue, breathlessness on exertion and pallor from chronic heavy bleeding - always check ferritin.

  • Red flag - postmenopausal bleeding

    Any bleeding after the menopause needs urgent gynaecology assessment to exclude endometrial pathology.

Treatment

How adenomyosis is treated in the UK.

NSAIDs and tranexamic acid first, then hormonal suppression - LNG-IUS, continuous pill, dienogest, GnRH options - with uterine-sparing procedures and hysterectomy held back for the right moment.

  • NSAIDs and tranexamic acid

    First-line symptom relief - mefenamic acid or naproxen for pain, tranexamic acid taken during the period to reduce bleeding by up to 50 percent.

  • Continuous combined pill

    A continuous or tricycled combined oral contraceptive suppresses ovulation and thins the endometrium - often halves bleeding and pain.

  • LNG-IUS (Mirena)

    Excellent evidence in adenomyosis - reduces menstrual blood loss by 70 to 80 percent at one year and eases pain. A first-line long-acting option.

  • Dienogest

    A progestogen with strong evidence in endometriosis and increasingly used in adenomyosis - reduces bleeding, pain and lesion size.

  • GnRH agonists

    Short-course medical menopause - shrinks the uterus and stops bleeding. Add-back HRT protects bone if used beyond 6 months.

  • Relugolix combination (Ryeqo)

    Oral GnRH antagonist with add-back oestradiol and norethisterone - approved by NICE (TA824) for heavy bleeding from uterine fibroids and used off-label in adenomyosis.

  • Uterine artery embolisation

    A radiology-led uterine-sparing option - reduces bulk symptoms and bleeding in selected women, with variable fertility outcomes.

  • HIFU and laparoscopic adenomyomectomy

    High-intensity focused ultrasound and laparoscopic excision of focal adenomyomas - uterine-sparing options in specialist centres.

Definitive surgery

Endometrial ablation and hysterectomy.

Endometrial ablation can help selected women with mild superficial disease when the family is complete, though results are less reliable than in simple heavy menstrual bleeding. Hysterectomy - laparoscopic, vaginal or abdominal - remains the definitive treatment for adenomyosis, curing bleeding and pain in one operation. It is offered when medical and uterine-sparing options have failed and childbearing is complete.

What this guide is based on

The sources behind every claim on this page.

UK national guidance, specialist society standards and international consensus, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or gynaecologist knows your history and imaging and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Heavy menstrual bleeding: assessment and management (NG88).

  • NICE. Relugolix-estradiol-norethisterone for treating moderate to severe symptoms of uterine fibroids (TA824).

  • RCOG. Green-top and patient information on heavy menstrual bleeding and pelvic pain.

  • ESHRE. Guideline on endometriosis (with reference to adenomyosis).

  • MUSA (Morphological Uterus Sonographic Assessment) consensus on ultrasound features of adenomyosis.

Red flags

When adenomyosis needs urgent attention.

Most adenomyosis is manageable in primary and community care. These are the situations that are not - and where urgent gynaecology input matters.

  • Postmenopausal bleeding

    Any bleeding after the menopause needs urgent two-week-wait gynaecology referral to exclude endometrial cancer.

  • Rapidly enlarging uterus

    A rapidly growing uterus, especially after the menopause, needs urgent imaging and specialist assessment.

  • Severe iron-deficiency anaemia

    Symptomatic anaemia with haemoglobin under 80 g/L may need urgent transfusion and inpatient care.

  • Recurrent miscarriage

    Two or more consecutive miscarriages with imaging features of adenomyosis - warrants a specialist fertility opinion before another attempt.

  • Acute severe pelvic pain

    Sudden severe pain with fever, faintness or peritonism needs same-day assessment to exclude other causes.

  • Suspicious ultrasound features

    Any mixed solid-cystic mass, thickened endometrium or unusual vascularity needs specialist imaging and often biopsy.

  • Failure of medical therapy

    Persistent heavy bleeding or pain after two well-chosen medical options - time to consider uterine-sparing surgery or hysterectomy.

  • Symptoms in pregnancy

    Adenomyosis raises risk of preterm birth, placental issues and postpartum haemorrhage - flag it to your obstetric team early.

  • New pelvic mass

    A newly palpable mass alongside bleeding change deserves prompt imaging - not everything boggy is adenomyosis.

Living with it

A treatable condition, with a clear ladder.

Four things that make the biggest difference day to day - tracking symptoms, treating the anaemia, giving hormonal options time and asking for uterine-sparing surgery when they fall short.

A quiet reminder

You are allowed to ask for imaging.

Heavy, painful periods that limit your life deserve investigation. A transvaginal ultrasound and, when needed, an MRI can settle the question in weeks.

  1. 01 Routine

    Track your cycle

    A simple cycle and pain diary makes it far easier to judge whether treatment is working - and to escalate at the right moment.

  2. 02 Iron

    Treat the anaemia, not just the bleed

    Iron replacement makes a bigger difference to daily energy than most women expect - ask for ferritin, not just haemoglobin.

  3. 03 Patience

    Give hormonal options time

    The LNG-IUS and continuous pill take three to six months to settle - stopping early is the commonest reason they seem not to work.

  4. 04 Escalate

    Ask about uterine-sparing options

    If medical therapy fails and you want to keep your uterus, embolisation, HIFU and adenomyomectomy are real options - ask for a specialist referral.

Frequently asked

Everything we get asked about adenomyosis.

Quick answers on imaging, fertility, the LNG-IUS, Ryeqo and when hysterectomy really is the right step.

  • What is adenomyosis?

    Adenomyosis is a condition where endometrial-type glands and stroma grow inside the muscular wall of the uterus (the myometrium). It is distinct from endometriosis, where similar tissue grows outside the uterus. It causes heavy periods, severe cramps, chronic pelvic pain and a boggy, enlarged, tender uterus.

  • How is adenomyosis different from endometriosis?

    Both involve endometrial-type tissue in the wrong place. Endometriosis grows outside the uterus - on the ovaries, tubes, bowel and peritoneum. Adenomyosis grows inside the uterine muscle. The two often coexist, but they cause different patterns of pain and need slightly different treatments.

  • How is adenomyosis diagnosed in the UK?

    Diagnosis is clinical and radiological. A transvaginal ultrasound is first line and looks for asymmetric myometrial thickening, junctional zone thickening greater than 12 mm and small myometrial cysts. MRI pelvis is the gold standard imaging test. A definitive tissue diagnosis needs a hysterectomy specimen and is not usually required to start treatment.

  • Does adenomyosis affect fertility?

    It can. Adenomyosis disrupts the junctional zone, which affects implantation and raises the risk of miscarriage and preterm birth. Women trying to conceive - especially with IVF - are often offered an ultra-long GnRH agonist protocol for two to three months before embryo transfer, which improves pregnancy rates in this group.

  • What is the best medical treatment for adenomyosis?

    For most women the LNG-IUS (Mirena) is the strongest first-line option - it reduces menstrual blood loss by 70 to 80 percent at one year and eases pain. Continuous combined pill, dienogest, GnRH agonists and the relugolix combination (Ryeqo) are all effective alternatives depending on your goals, side effects and whether fertility matters.

  • Do I need a hysterectomy?

    No - hysterectomy is definitive but it is the last step, not the first. Most women can be managed with medical therapy or uterine-sparing procedures such as embolisation, HIFU or laparoscopic adenomyomectomy. Hysterectomy is offered when symptoms persist despite well-chosen options and family is complete.

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