What is Endometriosis?

            Endometriosis is a female medical condition caused by the abnormal growth of endometrial tissue, the inner lining of a female’s uterus.1 Throughout the menstrual cycle, hormones cause the endometrium to grow and thicken. When a female becomes pregnant, the fertilized egg implants itself within the endometrium and begins growing inside of the uterus. If an egg, or ovum, is not fertilized during a menstrual cycle, hormones will signal the endometrium to break down and shed itself so that it can create fresh tissue for the next cycle. This endometrial discharge exits the vagina as menstrual blood. Endometriosis occurs when this endometrial tissue spreads and grows outside of the uterus. The displaced tissue is most commonly found in the pelvic region, including the outside of the uterus, ovaries, oviducts (fallopian tubes), or bowel area.2 Only in rare circumstances does endometriosis spread to areas beyond the pelvic region.


What are the Causes of Endometriosis?

            The exact cause of endometriosis remains uncertain. However, retrograde menstruation is considered the most probable explanation.3 Retrograde menstruation occurs when some of the endometrial discharge, released during a female’s menstrual period, does not follow the normal pathway out of the vagina; rather, it travels backward up the oviducts. These pieces of endometrial tissue then become stuck within the pelvic cavity and settle onto irregular places outside of the uterus.

            Hormones may also play a role. Endometriosis affects about one in ten women of reproductive age, which is the time between a female’s first menstruation and menopause – when she can no longer become pregnant.4 These childbearing years are when a woman’s estrogen levels are at their highest. Estrogen is the hormone that signals when the endometrial tissue should grow or shed itself during the menstrual cycle. After menopause, a female’s estrogen levels significantly drop and symptoms of endometriosis typically subside.


What are the Symptoms of Endometriosis?

            Symptoms of endometriosis include severe, long-term pelvic pain, abnormal vaginal bleeding, and infertility. Some women may have no symptoms at all.


  • Pelvic Pain

            The most common symptom of endometriosis is intense, chronic pain felt somewhere in the pelvic area where the displaced tissue is embedded, such as the lower pelvis, bowel or bladder area, or lower back.5 The pain can be felt before or during the menstrual period, during ovulation, or throughout the entire menstrual cycle. Although most women experience lower pelvic pain at some point during their menstrual cycles (especially during menstruation or ovulation), those suffering from endometriosis report much more severe levels of pain. If the tissue is implanted on the bowel or bladder, women may feel pain during bowel movements or urination. Pain during sex can also occur.

The abnormal tissue causes pelvic pain because it continues to thicken and shed like the tissue of the endometrium. The misplaced tissue, however, is unable to exit the body properly like the normal menstrual tissue. Healthy endometrial tissue inside the uterus passes through the vagina as blood during menstruation, and then continues its cycle of creating fresh tissue within the uterus. Endometrial tissue outside of the uterus is unable to be released and becomes stuck inside the body. This trapped tissue causes pain and irritates the surrounding areas.6 The inflamed areas can lead to the formation of scar tissue, or adhesions, which can cause organs or tissues to stick together. Another possible consequence is the formation of endometriomas, or cysts on your ovaries.7


  • Abnormal Vaginal Bleeding

            Another possible sign of endometriosis is abnormal bleeding.8 Women may have noticeably heavy periods or spotting, or bleeding in between periods. Some women may bleed after sex or have blood in their stools. However, abnormal bleeding does not always mean a female has endometriosis. Unusual bleeding can also be a sign of other causes, such as an STI or other infections. At the same time, some women with endometriosis may not have abnormal bleeding. The key is to notice if bleeding patterns are unusual for an individual and then pursue medical attention to figure out the underlying causes.


  • Infertility

            Infertility, or the inability to get pregnant, can be a sign of endometriosis. About 40% of infertile women have endometriosis.9 Some women go without noticing or diagnosing their endometriosis and only become aware of the condition once they find difficulties in becoming pregnant or have other health-related problems. Having endometriosis does not necessarily mean a female cannot have children, but means it may be more difficult for her to become pregnant. The more severe the endometriosis, the more difficult it may be to become pregnant. Women with mild cases of endometriosis may be able to become pregnant with little difficulty. Women with moderate to severe cases can also become pregnant but may need to have surgery, assisted reproductive technologies, or both.


How is Endometriosis Treated?

            There is no one straightforward cure for treating endometriosis. Treatment relies on the severity of the condition, the symptoms, and whether a woman wishes to be able to have children or not.

            If the endometriosis is not too severe, doctors will often recommend anti-inflammatory pain relievers, such as ibuprofen, to manage the pain. Hormonal medications, such as birth control pills or progestin-only medications, may be prescribed to control the growth of the endometrial tissue and reduce inflammation.10 The hormonal medications may reduce – but not completely remove – the endometrial patches.

Doctors may remove the patches of endometrial tissue through surgery if the pain becomes severe or interferes with the female’s ability to become pregnant. Surgery will relieve the patient’s pain, although temporarily. About 40-80% of women who undergo surgery have their endometriosis return again.11 Doctors may have patients take hormonal medications after surgery to prevent the endometriosis from becoming as severe as before.

            If the pain of endometriosis returns after surgery, a woman may consider having a hysterectomy. Endometriosis is the leading cause for hysterectomies in women between the ages of 18-35.12 A hysterectomy is the surgical removal of the uterus, after which a female will no longer be able to bare children. For the treatment of endometriosis, areas affected by the endometriosis are removed, which may include the ovaries. The chances of endometriosis returning after a hysterectomy are very small.

One way to detect endometriosis is to have a gynecological physician perform a bimanual vaginal examination during a woman’s regular health exam. Bimanual vaginal exams detect irregularities of the uterus and pelvic organs by having the doctor insert two fingers inside the patient’s vagina while using the other hand to press down on the lower pelvic region.13 This allows the doctor to feel the pelvic organs for abnormal growths or if any areas are unusually sensitive.


Support for Women with Endometriosis

Endometriosis is a common and often very painful condition for women. The following is a global forum for news and information on endometriosis. The website offers many useful resources for women with endometriosis, including support groups, treatment updates, and more information on endometriosis:



A new oral medicine called Elagolix is in development for the treatment of endometriosis. Led by researchers at the University of California at San Diego, clinical trials in the United States have begun for women suffering from endometriosis. The website here links to more information about the Violet Petal Study and how women can volunteer as patients to test the new drug:





1,5LeVay, S., Baldwin, J., Baldwin, J. (2009). Discovering human sexuality (pp. 38-40).

Sunderland, MA: Sinauer Associates, Inc.

2,3,6,7Mayo Clinic. (2 April 2013). Endometriosis. Accessed from


4,9,11,12Medline Plus. (29 April 2013). Endometriosis. U.S. National Library of Medicine.

Accessed from http://www.nlm.nih.gov/medlineplus/endometriosis.html

8,10Web MD. (7 July 2011). Endometriosis Health Center. Accessed from



Last Updated 22 May 2013.