# Adenomyosis: endo’s lesser-known cousin

> Heavy, painful periods with a bulky, tender womb? Meet adenomyosis.

Category: Conditions · 5 min read · Written by the Splash team · Sources checked October 2026
URL: https://splash.care/learn/conditions/adenomyosis

## Quick answer

- Adenomyosis is womb lining growing into the womb muscle.
- Heavy, painful periods are the main signs.
- It overlaps with endometriosis and fibroids, so a scan helps.
- The hormonal coil and other treatments can make a big difference.

In [adenomyosis](https://splash.care/learn/glossary/adenomyosis), the womb lining grows into the muscular wall of the womb. That tissue still responds to your cycle, which can make periods very painful and heavy. It is less talked about than [endometriosis](https://splash.care/learn/glossary/endometriosis), but it is not rare. [Endometriosis](https://splash.care/learn/conditions/endometriosis) UK says it affects about 1 in 10 people assigned female at birth, and it is common to have both.

## Signs

- Severe [period pain](https://splash.care/learn/period-care/cramp-relief) that can stop you doing usual activities
- [Heavy bleeding](https://splash.care/learn/period-care/heavy-periods)
- Pelvic pain, [bloating](https://splash.care/learn/body-literacy/bloating) or a feeling of fullness in your tummy
- Pain during or after sex
- Some people have no symptoms at all

The NHS says symptoms usually affect people over 35, but anyone who has periods can get it. You may be more likely to get it if you have given birth or have endometriosis. Adenomyosis can make it harder to get [pregnant](https://splash.care/learn/fertility-ttc/early-pregnancy-signs) and can raise the chance of miscarriage, so talk to a doctor if that matters to you.

## Why diagnosis can be slow

Symptoms overlap with endometriosis, fibroids, polyps and a thickened womb lining. A GP may examine you and arrange an ultrasound or MRI to look at the womb wall. NICE says that for heavy bleeding with significant period pain, a transvaginal ultrasound is the preferred first scan for suspected adenomyosis.

## Treatment

- The hormonal coil ([IUS](https://splash.care/learn/glossary/ius)), which thins the lining and lightens periods. NICE says to consider it as the first treatment for heavy bleeding in suspected or diagnosed adenomyosis.
- Other hormonal options, such as the [progestogen](https://splash.care/learn/glossary/progestogen)-only pill, combined pill or patch
- NSAIDs for pain or [tranexamic acid](https://splash.care/learn/glossary/tranexamic-acid) for heavy bleeding
- Heat pads and TENS machines for self-care
- If those do not work: a procedure to block the blood supply (uterine artery embolisation), or a hysterectomy, which is the only way to cure adenomyosis but means you cannot carry a pregnancy

> **Splash says:** a hot water bottle is a legit pain tool, not just a cosy one. Wrap it in a tea towel, and pair it with logging your flow so you can show how heavy things really are.

### When to see a doctor

See a GP if your periods are very painful or heavy, you bleed between periods or after sex, you have pelvic pain between periods, or pain during sex. The NHS says to ask for an urgent GP appointment or call 111 if your pain is severe or worse than usual and painkillers have not helped. Heavy bleeding with dizziness, breathlessness or a racing heart needs prompt medical advice.

## Sources

1. [NHS: Adenomyosis](https://www.nhs.uk/conditions/adenomyosis/)
2. [NICE guideline NG88: Heavy menstrual bleeding](https://www.nice.org.uk/guidance/ng88)
3. [Endometriosis UK: What is endometriosis?](https://www.endometriosis-uk.org/what-is-endometriosis)
4. [Cleveland Clinic: Adenomyosis](https://my.clevelandclinic.org/health/diseases/14167-adenomyosis)

This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).