Related Conditions

Endometriosis doesn’t happen in isolation, it’s usually tied to other conditions that can overlap in symptoms and make everything harder to figure out. Looking at those connections really shows how complex women’s health can be, especially when it comes to getting an accurate diagnosis.

Adenomyosis

Adenomyosis is a condition that is closely related to endometriosis and is often confused with it because of how similar the symptoms can be. According to the Cleveland Clinic, it is “when tissue similar to the lining of your uterus grows into the muscle wall of your uterus.”

This can cause the uterus to enlarge and lead to a range of symptoms. Cleveland Clinic also explains that adenomyosis can result in

“painful periods, heavy or prolonged menstrual bleeding and abdominal/pelvic pain."

Like endometriosis, symptoms don’t look the same for everyone. Some people may not notice anything at all, while others deal with symptoms that seriously affect their daily life. In fact, “about 1 in 3 people with adenomyosis don’t have signs or symptoms,” which can make it harder to identify.

Even though adenomyosis and endometriosis are different, they are often connected. The main difference is that adenomyosis happens when tissue grows within the uterine muscle, while endometriosis happens when similar tissue grows outside of the uterus.

Understanding adenomyosis as a related condition helps show how complex reproductive health can be and why diagnosis isn’t always straightforward.

Endometriosis and Infertility

Endometriosis is a condition where tissue similar to the lining of the uterus grows outside of it, affecting areas like the ovaries, fallopian tubes, and surrounding pelvic structures. The Mayo Clinic describes it as “an often-painful condition in which tissue that is similar to the inner lining of the uterus grows outside the uterus.”

Because this tissue responds to hormonal changes, it can lead to inflammation, pain, and scarring over time. These effects can also impact fertility and overall reproductive health.

Research shows that endometriosis may be connected to other health conditions as well. People with endometriosis may have a higher risk of developing autoimmune diseases like lupus, rheumatoid arthritis, and thyroid disorders, along with conditions like irritable bowel syndrome and pelvic inflammatory disease.

These connections highlight how complex endometriosis really is and help explain why diagnosis and treatment can be so challenging.

Resources

“Adenomyosis: Causes, Symptoms & Treatment.” Cleveland Clinic, 17 Apr. 2026, my.clevelandclinic.org/health/diseases/14167-adenomyosis.

“Endometriosis and Fertility.” Endometriosis and Fertility - Brigham and Women’s Hospital, www.brighamandwomens.org/obgyn/infertility-reproductive-surgery/endometriosis/endometriosis-and-fertility. Accessed 1 May 2026.

Elevationweb. “Endometriosis " Global Autoimmune Institute.” Global Autoimmune Institute " Empowering Solutions for Autoimmune Disease, 3 Mar. 2025, www.autoimmuneinstitute.org/autoimmune-resources/autoimmune-diseases-list/endometriosis/.