Adenomyosis: A Cause of Heavy Periods Few People Mention

TL;DR: Adenomyosis is when tissue like the womb lining grows into the muscle wall of the womb, often causing heavy bleeding and painful periods. It can be mistaken for fibroids or endometriosis, and can happen alongside them. A transvaginal ultrasound is usually the first test. The hormonal coil is a common first treatment, and only hysterectomy cures it. It can affect fertility, so tell your doctor if you want to get pregnant.

Maybe you have been told your heavy periods are down to fibroids, which is a reasonable first guess for a Black woman, and yet the treatment has not fixed the bleeding or the pain. Maybe the scan came back with a line about a "bulky uterus" and nobody explained it. Or maybe nothing has been found at all and you are still changing pads through the night. Adenomyosis is a condition many women have never heard of until it turns up in a report, and it is worth knowing the word before you next sit down with a doctor.

What is adenomyosis?

Adenomyosis is the presence of womb lining tissue inside the muscle of the womb. The womb is typically enlarged all over, and may double or triple in size, though it usually stays smaller than a womb at 12 weeks of pregnancy.

The NHS says it usually affects women over 35, but it can affect anyone who has periods. It is a benign condition, and symptoms may resolve after menopause.

What are the symptoms of adenomyosis?

The main symptoms are heavy bleeding and painful periods. The NHS also lists pelvic pain, tummy bloating or fullness, and pain during or after sex, which can come at any point in your cycle. Some women have no symptoms at all.

When researchers interviewed 31 women with adenomyosis in the US, the most common symptoms were heavy bleeding (87%), cramps (84%) and blood clots (84%), and heavy bleeding had the greatest impact on their lives. It was a small study, but those details will sound familiar to many women who plan their week around their flow.

Heavy bleeding month after month can also lead to anaemia. If you are tired, dizzy or breathless, ask for a blood test, and read about iron deficiency anaemia in women and iron-rich foods for heavy periods. Our post on heavy periods covers what counts as heavy and the wider list of causes.

How is adenomyosis different from fibroids and endometriosis?

All three can cause heavy, painful periods, and the NHS notes that overlapping symptoms can make diagnosis slow. The difference is where the tissue is and what it is made of.

• Adenomyosis: tissue like the womb lining grows into the muscle wall of the womb, so the whole womb tends to become enlarged.
• Fibroids: non-cancerous growths in or around the womb. They are usually separate lumps that an ultrasound can count and measure.
• Endometriosis: cells similar to the womb lining grow elsewhere in the body, and the procedure that can confirm it is a laparoscopy, where a camera goes through a small cut in the tummy.

You can also have more than one. Adenomyosis is most often found by chance in women being checked for endometriosis, fibroids or pelvic pain. This matters for Black women, because fibroids are so common. In one US ultrasound study, by age 50, more than 80% of Black women and nearly 70% of white women had developed fibroids. When fibroids are found, they can seem to explain everything. If your symptoms continue after fibroid treatment, or your pain seems out of proportion to what the scan showed, it is reasonable to ask, "Could this also be adenomyosis?"

For more on the two conditions it is most often confused with, read uterine fibroids: symptoms and treatment and endometriosis explained. Our pelvic pain guide covers other causes of pain.

How is adenomyosis diagnosed?

Usually with a scan, after your doctor has taken a history and examined you. NICE, the UK's health guidance body, recommends offering transvaginal ultrasound in preference to abdominal ultrasound or MRI to women with heavy periods who have significant period pain or a bulky, tender womb on examination. A transvaginal scan uses a small probe placed inside the vagina. If you would rather not have this or it is not suitable, NICE says a scan over the tummy or an MRI can be considered, although these have limitations.

NICE also says not to use MRI as a first-line test for heavy periods, so if one is suggested, ask what it will add and what it will cost where you live. A definitive diagnosis requires looking at tissue after a hysterectomy, so in practice most women are treated on the basis of their symptoms and imaging. If your scan report says "bulky uterus", ask what the sonographer saw and whether adenomyosis was considered.

NICE also reminds doctors that pain with heavy periods may come from endometriosis instead, so do not stop asking questions if the first treatment does not touch the pain.

What treatments help?

Treatment depends on your symptoms, your age and whether you want to become pregnant.

• The hormonal coil. NICE says to consider a levonorgestrel intrauterine system as the first treatment for heavy periods in women with suspected or diagnosed adenomyosis. A review of ten studies found it reduced pain, bleeding and the size of the womb for up to 36 months.
• Other hormonal medicines. The NHS lists the progestogen-only pill, combined pill and contraceptive patch. Merck's clinical manual cautions that combined pills are usually unsuccessful for adenomyosis, so ask your doctor what to expect. A progestogen called dienogest appeared to ease pain more than the coil in a review of six trials, all from Asia, although women using the coil had higher haemoglobin levels. Ask whether it is available where you live.
• Non-hormonal medicines. Anti-inflammatories for pain and tranexamic acid for bleeding can be taken during your period.
• Procedures. If these do not work, the NHS lists uterine artery embolisation and hysterectomy. Removing the womb is the only cure, and pregnancy is not possible afterwards.

Can you get pregnant with adenomyosis?

Many women with adenomyosis want to get pregnant, and it may take more planning. The NHS says it can make it difficult to get pregnant and may increase the risk of miscarriage.

A review of 17 observational studies found that women with adenomyosis having fertility treatment had lower odds of clinical pregnancy and about twice the odds of miscarriage. It also linked adenomyosis with higher risks of pre-eclampsia, preterm birth and caesarean delivery, and advised close monitoring during pregnancy. These are increased risks, and many women still have healthy pregnancies.

If you want children, say so at your very first appointment, because it changes which treatments are on the table. The coil and other hormonal options are contraceptives, so you will need a plan for when to stop. We look at the overlapping question for fibroids in fibroids and fertility.

What should I bring to my appointment?

A clear record of your bleeding and pain. Note how often you change pads or tampons, whether you pass clots, how many days the pain stops you working, whether sex hurts, and whether anything you have tried has helped. Ask for your ultrasound report and keep a copy. Our guide to periods sets out which symptoms should take you to a doctor.

Asele's symptom logging can keep that record across several cycles, and the Health Brief turns it into a short summary to take with you. You can find us at Asele.

This post is education, not medical advice. Please speak to a qualified clinician about your own symptoms.

References

1. Merck Manual Professional Version. Uterine adenomyosis. merckmanuals.com
2. NHS. Adenomyosis. nhs.uk
3. Nelsen LM, et al. Experience of symptoms and disease impact in patients with adenomyosis. The Patient, 2018. pubmed.ncbi.nlm.nih.gov
4. NHS. Fibroids. nhs.uk
5. NHS. Endometriosis. nhs.uk
6. Baird DD, et al. High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence. American Journal of Obstetrics and Gynecology, 2003. pubmed.ncbi.nlm.nih.gov
7. NICE. Heavy menstrual bleeding: assessment and management (NG88). nice.org.uk
8. Abbas AM, et al. The role of levonorgestrel intra-uterine system in the management of adenomyosis: a systematic review and meta-analysis of prospective studies. Acta Obstetricia et Gynecologica Scandinavica, 2020. pubmed.ncbi.nlm.nih.gov
9. Akhigbe RE, et al. Comparison of the effectiveness of levonorgestrel intrauterine system and dienogest in the management of adenomyosis: a systematic review and meta-analysis. European Journal of Obstetrics & Gynecology and Reproductive Biology, 2024. pubmed.ncbi.nlm.nih.gov
10. Nirgianakis K, et al. Fertility, pregnancy and neonatal outcomes of patients with adenomyosis: a systematic review and meta-analysis. Reproductive BioMedicine Online, 2021. pubmed.ncbi.nlm.nih.gov