Let´s talk about Adenomyosis

July 15, 2025 . elenaw

What is Adenomyosis?

Adenomyosis is a chronic gynecological condition that occurs when endometrial tissue (the lining of the uterus) grows into the muscular wall of the uterus. Experts generally distinguish between localized adenomyosis, often associated with fibroids (myomas), and a diffuse form, which affects the entire uterus.

Throughout the menstrual cycle, the displaced endometrial tissue behaves similarly to normal tissue: it thickens, falls apart, and bleeds. However, because this tissue is trapped within the muscle, it cannot exit the body as it normally would. As a result, the uterus may become enlarged, leading to painful and prolonged periods.

What symptoms do people with Adenomyosis experience?

In addition to increased menstrual pain, adenomyosis can cause chronic pelvic and abdominal pain, which may worsen during sexual intercourse. Many patients also experience retrograde menstruation, where menstrual blood flows backward through the fallopian tubes into the abdominal cavity. This reverse flow can interfere with egg movement and alter the mucosal lining, contributing to fertility issues and an increased risk of miscarriage.

How does the condition develop?

Although the exact cause of adenomyosis is still unknown, several theories have been proposed:

1. Disruption of the Junctional Zone

The junctional zone is the interface between the endometrial lining and the muscular layer of the uterus. If this zone is disrupted, mucosal cells can migrate into the muscle, where they begin to grow abnormally.

2. Uterine Contractions

Another theory suggests that strong uterine contractions can create tiny tears or fissures between the endometrial lining and the muscle. In response, the body may produce excess estrogen, promoting the growth and implantation of the misplaced tissue.

What Are the Risk Factors?

While the exact causes are uncertain, several factors may increase the risk of developing adenomyosis:

Multiple pregnancies

Advancing age

Short menstrual cycles

Uterine surgery or procedures (e.g., C-sections)

Early onset of menstruation

Obesity

What is the difference between Adenomyosis and Endometriosis?

Because they share similar symptoms, adenomyosis is sometimes mistaken for or grouped with endometriosis. However, from a molecular and epigenetic perspective, they are distinct chronic diseases.

Endometriosis occurs when endometrial-like tissue grows outside the uterus on organs such as the ovaries, fallopian tubes, bladder, or intestines.

Adenomyosis, in contrast, occurs within the muscular wall of the uterus.

Although different, both conditions can occur simultaneously, affecting about 22% of patients with either disease.

For more information – read more about Adenomyosis here and here.

And for a break-down of Endometriosis – check out our previous blog post.