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The difference between endometriosis and adenomyosis

Did you know that March is Endometriosis Awareness Month in the UK?

According to Endometriosis UK, endometriosis affects 1 in 10 women and those assigned female at birth. That’s over 1.5 million women.

Despite these sobering numbers, endometriosis is often considered a taboo topic by society, fuelled by the outdated narrative that women should “put up with” menstrual pain— no matter its severity.

If you are in the process of being diagnosed with endometriosis or an associated gynaecological condition, you might have heard of adenomyosis, or be grappling with its distressing symptoms.

There are many similarities between endometriosis and adenomyosis, the biggest one being that they are both endometrial conditions. However, endometriosis and adenomyosis are not the same.

What is endometriosis?

Endometriosis occurs when the tissue that lines the inside of your womb (endometrium) grows outside of your womb. This tissue can develop on your ovaries, fallopian tubes, the lining of the inside of your abdomen and your bowel or bladder.

The National Library of Medicine reports: "Endometriosis is a chronic disease, which is under-diagnosed, under-reported, and under-researched. It is defined as the presence of endometrial tissue outside the uterus and is found in women of all ethnic and social groups".

"Endometriosis is a chronic disease, which is under-diagnosed, under-reported, and under-researched. It is defined as the presence of endometrial tissue outside the uterus and is found in women of all ethnic and social groups". - The National Library of Medicine

What is adenomyosis?

Adenomyosis occurs when your endometrium (the cells that make up the lining of the womb) starts to grow within the muscular wall of the womb.

It too results in chronic pelvic pain and excruciating periods.

While endometriosis and adenomyosis are separate endometrial conditions, they share some similarities, including:

Similar symptoms

Harvard Health reports that the most common symptoms of endometriosis are heavy periods, as well as pelvic or abdominal pain before or during menstruation. Women with endometriosis may experience pain during sexual intercourse and urination, alongside bowel symptoms such as diarrhoea and constipation.

According to the NHS, the most common symptoms of adenomyosis are heavy or painful periods and pelvic pain. Adenomyosis may cause women to experience painful sexual intercourse and bowel movements, but these symptoms are less common.

Similar diagnosis times

Both conditions can take years to diagnose.

Endometriosis symptoms vary across women, which can make it difficult to diagnose. Our Endometriosis Matters 2020 report found that 33% of women waited seven years or more for an endometriosis diagnosis. This statistic reflects the many challenges faced by women when trying to reach a confirmed diagnosis.

It can also take years to receive a diagnosis for adenomyosis, because symptoms vary across women. Symptoms of adenomyosis are also similar to that of other gynaecological conditions.

Some similar treatment options

Hormonal medication such as the combined oral contraceptive (the pill) or the intrauterine system (commonly known as the coil) might be prescribed to treat both adenomyosis and endometriosis.

The combined pill can provide long-term relief by making periods lighter and less painful (for some women).

The coil is a form of contraception that works by releasing a progestogen hormone called levonorgestrel. The hormone stops the lining of the womb from growing quickly, lessening pain and stopping periods (for some women).

While endometriosis and adenomyosis have similar symptoms and diagnosis times, they also have key differences, including:

Endometriosis and adenomyosis affect different age groups

Endometriosis and adenomyosis can affect any person with a period. However endometriosis most commonly impacts women between the ages of 25 and 40.

Adenomyosis is most common in women aged between 40 and 50.

Endometriosis requires surgery to diagnose

An endometriosis diagnosis can only be confirmed through laparoscopy surgery.

During a laparoscopy, a small cut is made at your belly button and a thin tube with a tiny camera (laparoscope) is passed through your tummy. Images from the laparoscope are sent to a video monitor. These help a specialist Consultant identify any endometrial tissue.

A small sample of your tissue may be taken to test for endometrial tissue. This examination does not require any overnight stay and is performed under anaesthetic.

A transvaginal (through the vagina) ultrasound scan is used to diagnose at least 50% of adenomyosis cases. During this ultrasound, a small probe is gently inserted into your vagina. Images are then gathered from this and sent to a monitor. If the ultrasound scan does not clearly reveal if you have adenomyosis, your GP might recommend an MRI scan.

The conditions impact fertility differently

Adenomyosis does not decrease the likelihood of you getting pregnant. But it can increase your risk of experiencing a miscarriage or having a premature baby.

On the other hand, endometriosis can cause infertility and repeated miscarriages. Reports show that 30 to 50% of women with endometriosis can suffer from infertility. Surgery can improve the chances of pregnancy for women with endometriosis. The NHS states removing endometrial tissue through laser treatment or keyhole surgery can improve the likelihood of getting pregnant.