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Health condition · Clinically reviewed

Endometrial hyperplasia, the precursor lesion that treatment reliably reverses.

A common cause of abnormal bleeding, and one where the WHO 2014 split between hyperplasia without atypia and atypical hyperplasia changes everything about the plan.

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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 RCOG, BSGE, BGCS and RCPath standards you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including the WHO 2014 classification and Lynch syndrome screening.

Key facts

Endometrial hyperplasia at a glance.

The essentials, in plain English: what it is, how the WHO 2014 split works, and how UK gynaecology approaches treatment.

  • What it is

    Excessive proliferation of the endometrial glands, driven by unopposed oestrogen. A precursor lesion to endometrial cancer in a subset of women.

  • Classification

    WHO 2014 splits it in two: hyperplasia without atypia, and atypical hyperplasia (endometrial intraepithelial neoplasia, EIN).

  • Progression risk

    Without atypia: under 5% progress to cancer over 20 years. With atypia: around 30%, and roughly 40% have an occult cancer at hysterectomy.

  • Typical presentation

    Abnormal uterine bleeding: postmenopausal bleeding, intermenstrual bleeding, heavy or prolonged periods.

  • First-line medical

    The levonorgestrel intrauterine system (Mirena) for hyperplasia without atypia: 90 to 95% regression at five years.

  • Definitive surgery

    Total hysterectomy with bilateral salpingo-oophorectomy for atypical hyperplasia in women who have completed their family.

Why this guide matters

Two diagnoses, two very different plans.

The WHO 2014 split matters enormously. Hyperplasia without atypia is a medical problem. Atypical hyperplasia is a surgical one, with an occult cancer risk that changes the conversation.

  • Without atypia: low risk, medical care

    Under 5% progress over 20 years. The LNG-IUS achieves regression in 90 to 95% of women, with six-monthly surveillance biopsies until two are negative.

  • Atypical: high risk, surgical decision

    Around 30% progress, and around 40% of women have an occult endometrial cancer at hysterectomy. Total hysterectomy with BSO is the recommended standard.

  • Fertility can be preserved carefully

    In selected younger women with atypical hyperplasia, fertility-sparing pathways using the LNG-IUS and intensive surveillance are offered in specialist centres.

How the diagnosis is made

From first bleed to a settled plan.

The steps a UK gynaecology team will normally follow, in order, so you know what to expect and why.

  1. 01

    Assessing

    History and bleeding pattern

    A careful history: postmenopausal bleeding, intermenstrual bleeding, heavy or prolonged periods, and the risk factors that point to unopposed oestrogen.

  2. 02

    Assessing

    Risk-factor review

    Obesity, PCOS, tamoxifen, unopposed oestrogen HRT, nulliparity, early menarche or late menopause and a family history suggestive of Lynch syndrome.

  3. 03

    Assessing

    Two-week-wait for PMB

    Any bleeding after the menopause meets the two-week-wait threshold for suspected gynaecological cancer in UK practice.

  4. 04

    Confirming

    Transvaginal ultrasound

    Measures endometrial thickness. Postmenopausal thickness above 4 mm warrants an endometrial biopsy; in premenopausal women the picture is more clinical.

  5. 05

    Confirming

    Endometrial sampling

    Outpatient Pipelle biopsy, hysteroscopy with directed biopsy, or dilatation and curettage. See our diagnostic hysteroscopy guide for what to expect.

  6. 06

    Confirming

    Specialist gynae pathology

    Histology is reported to WHO 2014 criteria by a specialist gynae pathologist: without atypia, or atypical hyperplasia (EIN).

  7. 07

    Preparing

    Lynch screening on atypia

    Mismatch-repair immunohistochemistry (MMR IHC) is offered on atypical hyperplasia and endometrial cancer specimens per RCPath, with genetics referral if abnormal.

Typical timeline: two-week-wait referral, ultrasound and biopsy within days to weeks.

Symptoms

The patterns that bring women in.

Bleeding is the story. Postmenopausal bleeding, spotting between periods and prolonged, heavy cycles are the common presentations, alongside the risk factors that make it more likely.

  • Postmenopausal bleeding

    Any bleeding after the menopause is abnormal until proven otherwise, and always warrants urgent investigation.

  • Intermenstrual bleeding

    Bleeding between periods, spotting or bleeding after sex in premenopausal women deserves review.

  • Heavy menstrual bleeding

    Periods heavy enough to affect quality of life, especially when persistent or worsening.

  • Prolonged or irregular periods

    Long, unpredictable cycles, common in PCOS and perimenopause and a classic pattern for unopposed oestrogen exposure.

  • Bleeding on tamoxifen

    Tamoxifen raises the risk of hyperplasia and cancer, so any bleeding on treatment warrants prompt review.

  • Bleeding on HRT

    Unscheduled bleeding on HRT, particularly on unopposed oestrogen, needs endometrial assessment.

  • Obesity and metabolic risk

    Higher BMI drives peripheral aromatisation of androgens to oestrogen, one of the strongest risk factors.

  • Red flag - postmenopausal bleeding

    A single episode of postmenopausal bleeding is enough to trigger a two-week-wait referral in the UK.

Treatment

How endometrial hyperplasia is treated in the UK.

Lifestyle and the LNG-IUS first for hyperplasia without atypia. Hysterectomy for atypical disease, with a specialist fertility-sparing route for carefully selected younger women.

  • Lifestyle and risk reduction

    Weight loss, optimising diabetes and reviewing HRT or tamoxifen where possible. Modifies the underlying oestrogen drive and improves regression rates.

  • LNG-IUS (Mirena)

    First-line for hyperplasia without atypia. Minimum five years, with regression in around 90 to 95%. See our Mirena clinic guide.

  • Continuous oral progestogen

    Medroxyprogesterone acetate 10 to 20 mg or norethisterone 15 mg daily as an alternative to the LNG-IUS where an intrauterine device is not tolerated or accepted.

  • Surveillance biopsies

    Endometrial biopsy every six months until two consecutive negatives, then annually, per RCOG and BSGE.

  • Hysteroscopy and biopsy

    For persistent, progressing or medically resistant disease, and for targeted sampling of focal lesions.

  • Laparoscopic hysterectomy

    Definitive treatment: laparoscopic or robotic hysterectomy, with bilateral salpingo-oophorectomy in postmenopausal women or atypical disease.

  • Fertility-sparing pathway

    Selective in young women with atypical hyperplasia: LNG-IUS with or without high-dose oral progestogen and intensive three to six monthly hysteroscopic surveillance.

  • Adjunct GnRH agonist

    Sometimes used alongside the LNG-IUS in women with very high BMI or those unfit for surgery, under specialist care.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, 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 can tell you which parts apply to you. If in doubt, get seen.

  • RCOG and BSGE. Management of Endometrial Hyperplasia (Green-top Guideline No. 67), 2016.

  • British Gynaecological Cancer Society (BGCS). Uterine cancer guidelines.

  • RCPath. Dataset for histopathological reporting of endometrial cancer, including MMR testing.

  • NICE. Suspected cancer: recognition and referral (NG12), including postmenopausal bleeding.

Red flags

When bleeding needs urgent attention.

Most abnormal bleeding is benign, but a small group of features needs a fast pathway into specialist gynaecology.

  • Postmenopausal bleeding

    Any bleeding after 12 months without periods, however light, meets the two-week-wait threshold and needs urgent gynaecology review.

  • Bleeding on tamoxifen

    Tamoxifen raises the risk of hyperplasia and cancer. Any abnormal bleeding on treatment warrants prompt endometrial assessment.

  • Bleeding on unopposed oestrogen HRT

    Unopposed systemic oestrogen in a woman with a uterus is a strong risk factor. Bleeding on treatment needs review and a regimen change.

  • Atypical hyperplasia on biopsy

    Around 40% of women with atypical hyperplasia have an occult endometrial cancer at hysterectomy: this is a surgical decision, not a wait-and-see.

  • Persistent bleeding on the LNG-IUS

    Ongoing bleeding despite a well-sited coil, especially with a raised BMI, deserves hysteroscopic assessment rather than reassurance.

  • Family history suggestive of Lynch

    Multiple relatives with endometrial, bowel or ovarian cancer at a young age warrants MMR testing and a genetics referral.

  • Rapidly enlarging uterus

    A rapidly enlarging uterus, particularly with bleeding, may signal something more than benign hyperplasia and needs imaging.

  • Progression on surveillance

    A change from without atypia to atypical hyperplasia on serial biopsy shifts the whole conversation towards definitive surgery.

  • Bleeding after negative surveillance

    New bleeding after two negative biopsies is not simply reassurance failing: it warrants repeat imaging and hysteroscopy.

Living with it

A treatable diagnosis, with a clear pathway.

Weight, follow-up, family history and fertility are the four themes that shape day-to-day care between clinic visits.

A quiet reminder

Turning up for the biopsy is the treatment.

The LNG-IUS does the medical work. The surveillance schedule is what proves it has worked, and catches the small number who need more.

  1. 01 Weight

    Weight loss changes the odds

    Reducing BMI cuts peripheral oestrogen production and improves regression rates on the LNG-IUS. Small, sustained losses matter.

  2. 02 Follow-up

    Turn up for surveillance

    Six-monthly biopsies feel like a lot, but they are how we catch progression early and confirm regression on treatment.

  3. 03 Family

    Ask about Lynch

    If atypical hyperplasia or endometrial cancer runs in the family, ask about MMR testing and a genetics referral for you and your relatives.

  4. 04 Fertility

    Fertility-sparing is possible

    For carefully selected women with atypical hyperplasia, fertility-sparing care is real, but it needs a specialist centre and intensive follow-up.

Frequently asked

Everything we get asked about endometrial hyperplasia.

Quick answers on classification, the Mirena, atypia, fertility and follow-up.

  • What is endometrial hyperplasia?

    It is excessive proliferation of the glands lining the uterus, driven by unopposed oestrogen. It is classified in two groups: hyperplasia without atypia and atypical hyperplasia, also called endometrial intraepithelial neoplasia (EIN).

  • Is it cancer?

    No, but it is a precursor. Hyperplasia without atypia carries a low progression risk of under 5% over 20 years. Atypical hyperplasia carries around a 30% progression risk and, importantly, roughly 40% of women who go straight to hysterectomy are found to have an occult endometrial cancer already present.

  • What causes it?

    Prolonged exposure to oestrogen unopposed by progesterone. The main drivers are obesity (through peripheral aromatisation), PCOS with anovulation, tamoxifen, unopposed oestrogen HRT, oestrogen-secreting tumours, nulliparity, early menarche and late menopause. Lynch syndrome raises the underlying risk.

  • How is it diagnosed?

    By an endometrial biopsy: outpatient Pipelle, hysteroscopy with directed biopsy, or dilatation and curettage. Transvaginal ultrasound guides who needs sampling, particularly the 4 mm postmenopausal threshold. Histology is reported by specialist gynae pathology to WHO 2014 criteria.

  • What is the first-line treatment for hyperplasia without atypia?

    The levonorgestrel intrauterine system (Mirena) for at least five years. Around 90 to 95% of women regress on treatment. Continuous oral progestogens are an alternative. Surveillance biopsies every six months confirm regression.

  • What if I have atypical hyperplasia and still want children?

    A fertility-sparing pathway can be offered in specialist centres, with an LNG-IUS, sometimes plus high-dose oral progestogen, and intensive hysteroscopic surveillance every three to six months. Definitive hysterectomy is then recommended once the family is complete. It requires careful counselling because recurrence and coexisting cancer risks are real.

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