Endometriosis is a condition where the lining of the uterus or endometrium grows outside the uterus. The endometrium normally thickens as part of the menstrual cycle to prepare the body for a potential pregnancy. If no pregnancy occurs, this tissue breaks down and is expelled with menstruation. However, if this tissue develops elsewhere in the body, it cannot be expelled, causing swelling, pain, and potentially permanent internal scarring. 

Endometriosis can also be associated with several other conditions.

Pregnancy complications and infertility

One of the most common complications of endometriosis is impaired fertility. Women with endometriosis may struggle to conceive. This could be due to endometrial growth or scar tissue blocking the tubes connecting the ovaries to the uterus, or from direct damage to the ovaries. There are treatments to help aid fertility in these situations.

Endometriosis may also increase the risk of complications during pregnancy, including premature birth.

Ovarian cysts

Endometriosis can make the development of ovarian cysts more likely. Fluid-filled sacs may develop on the ovaries, where the eggs develop and are stored. These do not cause an issue most of the time, but if they rupture or grow too large they may restrict blood flow to the ovaries or put pressure on the surrounding organs such as the stomach and bladder. This can result in pain, difficulty emptying the bowels, frequent need to urinate, bloating, and abnormal periods.

Rarely, the ovarian cyst may be cancerous.

Ovarian cancer

Several forms of cancer appear to be more common in people with endometriosis. In particular, ovarian cancer may occur more frequently in endometriosis patients compared to the general population. It is important to note, however, that while the risk may be increased, the overall chance of developing ovarian cancer is still very low in endometriosis patients.

Bladder and bowel problems

Endometriosis can affect the bowel and bladder. If surgery is required to remove the endometrial tissue, a temporary urostomy or colostomy bag may be required to remove waste products from the bladder or bowel respectively while the body heals.

Autoimmune diseases

Endometriosis may be associated with a higher risk of developing some autoimmune diseases, where the immune system mistakenly attacks healthy tissues. One study, published in the scientific journal Human Reproduction in 2002, found that the incidence of several disorders, including multiple sclerosis (MS), lupus, Sjögren’s syndrome, and rheumatoid arthritis, was significantly higher in women with endometriosis compared to the general U.S. population. These findings were similar in a study published in 2011  that investigated the frequency of autoimmune disorders in endometriosis in a Danish population.

Both studies found that while there was a higher rate of an autoimmune disorder co-occurring with endometriosis than alone, the overall chance of developing a second disorder was very low.


Adenomyosis is a similar but distinct condition to endometriosis. However, the two conditions can occur together. Adenomyosis is characterized by endometrial cells developing inside the muscular wall of the uterus, as opposed to lining it. It can cause the uterus to become enlarged, leading to pain and heavy bleeding.

It is possible that the two conditions may be associated with each other, as they may have similar risk factors.

Uterine fibroids

Uterine fibroids are noncancerous (benign) tumors that develop inside the walls of the uterus. They consist of muscle fibers and connective tissue and can vary in size, rapidity of growth, and location.

Some studies have suggested that uterine fibroids occur frequently alongside endometriosis.


Endometriosis News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.