Adenomyosis: The Common Condition That Too Many Women Have Never Heard Of

March is Endometriosis Awareness Month, and while endometriosis rightly receives growing attention, I want to talk about a closely related condition that remains far less well known: adenomyosis. In my clinic, I see women every week who have been struggling with heavy, painful periods for years — sometimes decades — without ever being told that adenomyosis could be the cause. It is one of the most common conditions I diagnose, and one of the most under-recognised in gynaecology.

If you have never heard of adenomyosis, you are far from alone. But understanding it could be the key to finally getting answers about your symptoms.

What exactly is adenomyosis?

Adenomyosis occurs when the tissue that normally lines the inside of the uterus — the endometrium — begins to grow into the muscular wall of the uterus itself, known as the myometrium. Each month, this misplaced tissue responds to hormonal changes just as the normal lining does: it thickens, breaks down, and bleeds. But because it is trapped within the muscle wall, it has nowhere to go. This leads to localised inflammation, swelling, and over time, a bulky, enlarged uterus.

Adenomyosis can be diffuse, affecting large areas of the uterine wall, or focal, forming a distinct mass called an adenomyoma. Both forms can cause significant symptoms, though the pattern and severity can vary considerably from one woman to another. Some women have extensive adenomyosis visible on imaging but relatively mild symptoms, while others have more localised disease that causes debilitating pain.

How is adenomyosis different from endometriosis?

This is a question I am asked frequently, and it is an important distinction. Both conditions involve endometrial-like tissue growing where it should not, but the location is different:

• Endometriosis: tissue grows outside the uterus — on the ovaries, fallopian tubes, bowel, bladder, and other pelvic structures
• Adenomyosis: tissue grows into the muscular wall of the uterus itself

The two conditions frequently coexist. Research suggests that up to 40–50% of women with endometriosis also have adenomyosis, which is why it is so important to look for both when investigating pelvic pain or heavy periods. They share some symptoms — particularly painful periods — but adenomyosis tends to cause heavier menstrual bleeding, while endometriosis is more commonly associated with deep pelvic pain and pain during intercourse.

Importantly, they may require different treatment approaches, which is why an accurate diagnosis matters.

Recognising the symptoms

The symptoms of adenomyosis can range from mild to severely disabling. The most common ones I see in my patients include:

• Heavy menstrual bleeding: Periods that are prolonged, excessively heavy, or require frequent changing of pads or tampons. Many women describe flooding, passing large clots, or needing to double up on protection
• Painful periods (dysmenorrhoea): Cramping that can be intense, often starting before the period and lasting throughout. This pain may not respond well to over-the-counter painkillers
• Chronic pelvic pain: A dull, persistent aching or pressure in the lower abdomen that may be present throughout the cycle, not only during menstruation
• Bloating and pelvic pressure: A feeling of heaviness or fullness in the pelvis, sometimes described as a sensation of bearing down. Some women notice visible abdominal distension, sometimes called "adeno belly"
• Pain during intercourse: Particularly deep pain, which can significantly affect intimate relationships
• Fatigue: Often related to chronic blood loss leading to iron deficiency anaemia, but also linked to the inflammatory nature of the condition itself

Many women I meet have been told their heavy periods are "just their normal" or have been managing with increasing doses of painkillers for years. If this sounds familiar, I would encourage you to seek a specialist opinion.

How is adenomyosis diagnosed?

Historically, adenomyosis could only be confirmed by examining the uterus after hysterectomy. This meant that for many years, it was considered a diagnosis made primarily in women over 40. We now know this is not the case — adenomyosis affects women of all ages, including those in their twenties and thirties.

The advancement that has changed everything is specialist imaging:

• Transvaginal ultrasound (TVS): When performed by an experienced operator, TVS can identify the characteristic features of adenomyosis with high accuracy. These include asymmetric thickening of the myometrium, myometrial cysts, a heterogeneous appearance of the uterine wall, and a "question mark" shape to the uterus. This is the first-line investigation I use in my practice
• MRI: Magnetic resonance imaging provides excellent soft tissue detail and can be particularly useful for mapping the extent of disease, differentiating adenomyosis from fibroids, and planning surgical treatment. It is especially helpful in complex cases or where ultrasound findings are inconclusive

The quality of diagnosis depends heavily on the experience of the person performing and interpreting the scan. A standard ultrasound may miss adenomyosis entirely if the sonographer is not specifically trained to look for it. This is one of the reasons why specialist assessment is so valuable.

Treatment options: what can be done?

The good news is that there are multiple treatment options for adenomyosis, and the right approach depends on the severity of your symptoms, your age, and whether you wish to preserve your fertility. I always work with my patients to develop an individualised plan.

Hormonal treatments:

• Mirena coil (levonorgestrel intrauterine system): This is often my first-line recommendation. The Mirena releases progesterone directly into the uterus, thinning the lining and significantly reducing both bleeding and pain. Many women experience a dramatic improvement within 3–6 months
• Combined oral contraceptive pill: Taken continuously (without the usual break), this can suppress ovulation and reduce the cyclical hormonal stimulation that drives adenomyosis symptoms
• Progestogen-only treatments: Oral progestogens, the desogestrel pill, or injectable progestogens can all help to manage bleeding and pain
• GnRH analogues: These medications temporarily suppress oestrogen production, effectively creating a reversible menopause. They can be very effective for symptom relief but are typically used short-term or as a bridge to other treatment, due to side effects related to low oestrogen

Non-hormonal medical treatment:

• Tranexamic acid: Reduces menstrual blood loss and can be taken during your period only
• Anti-inflammatory painkillers (NSAIDs): Mefenamic acid and ibuprofen can help with both pain and bleeding

Surgical options:

• Hysterectomy: This remains the only definitive cure for adenomyosis. For women who have completed their families and whose symptoms are severely affecting their quality of life, it can be truly life-changing. Modern surgical techniques, including laparoscopic and robotic approaches, mean shorter recovery times and better outcomes
• Adenomyomectomy: In selected cases, particularly focal adenomyosis in women wishing to preserve fertility, surgical excision of the adenomyotic tissue may be considered. This is a more complex procedure and requires careful patient selection

Adenomyosis and fertility

This is an area of growing research and one that many of my younger patients are understandably concerned about. The relationship between adenomyosis and fertility is complex and not yet fully understood, but the evidence is building.

Adenomyosis may affect fertility in several ways: it can alter the way the uterus contracts, disrupt implantation of the embryo, and create a less favourable environment within the uterine cavity. Studies suggest that women with adenomyosis may have lower implantation rates and higher miscarriage rates, including in the context of IVF treatment.

However, this does not mean that pregnancy is impossible. Many women with adenomyosis conceive naturally, and for those undergoing fertility treatment, awareness of the condition allows for better management. Pre-treatment with GnRH analogues, for instance, has shown promise in improving IVF outcomes for women with adenomyosis. If you are trying to conceive and have symptoms suggestive of adenomyosis, I would recommend a thorough evaluation before starting treatment.

When should you seek help?

I would encourage any woman to seek a specialist assessment if she experiences:

• Periods that are becoming progressively heavier or more painful
• Menstrual bleeding lasting more than 7 days
• Passing large clots or flooding through protection
• Pelvic pain that persists outside of menstruation
• Symptoms of anaemia — fatigue, breathlessness, pallor
• Difficulty conceiving, particularly with painful or heavy periods
• A feeling that something is not right, even if you have been told your symptoms are "normal"

You know your own body. If your periods are significantly affecting your ability to work, exercise, socialise, or simply enjoy your life, that is not something you should accept as inevitable. Adenomyosis is treatable, and the first step is getting the right diagnosis.