Diseases and Disorders > Endometriosis > Overview

The Facts About Endometriosis

Knowing the basics of this commonly overlooked disease can empower more women to seek treatment.

A woman looks at a tablet with a doctor speaking on it.

Do you know what endometriosis is? It's not surprising if you don't. One survey found about 33 percent of women don't know what this disease is, and 45 percent can't name any symptoms. Yet endometriosis affects more than 6.5 million American women, and if left untreated, it can cause a plethora of problems, ranging from pain to infertility.

Understanding what to look for can prepare women to help themselves and each other with vital information about this common medical problem.

What is endometriosis?

First a quick physiology lesson: The inner lining of the uterus is made of a dynamic layer called the endometrium. This tissue thickens and develops in response to hormone changes leading up to ovulation and then largely sloughs off when a fertilized egg doesn’t implant at the end of a menstrual cycle. The uterus is built for this process and has a handy exit route for this material through the vagina (this is what is experienced as a period). In endometriosis, tissue that is functionally very similar to the endometrium, called endometrium-like, is found outside of the controlled environment of the uterus. 

This endometrium-like tissue is most often located in the pelvic cavity adherent to structures such as the ovaries, fallopian tubes, bladder and intestines. It is not limited to the pelvis however and lesions have been found in such varied locations as the lung, belly button, and brain. This interloping tissue goes through the same cyclical build-up and break-down in response to circulating hormones, producing debris in areas that are not prepared to manage it.

Who gets endometriosis?

Endometriosis affects 1 in 10 women of reproductive age, with the most likely occurrence in women ages 30 to 49. In the past, doctors believed that endometriosis was more likely to affect white women than Black or Hispanic women. In large part, this was based on a 1951 study that said Black women did not get endometriosis due to genetic factors. While the medical community now knows this is inaccurate, there is still a discrepancy in the rates at which women of color are diagnosed with endometriosis. In fact, white women are about twice as likely to be diagnosed as Black and Hispanic women, and Asian women see the highest rates of diagnosis. Asian women are also more likely to be diagnosed with an advanced stage of endometriosis, although the reason is unclear.

This discrepancy in diagnosis makes it difficult to know the exact demographic information for who gets endometriosis, but recent studies have indicated that women of all races and ethnicities of reproductive age can be affected by the condition.

Risk factors for endometriosis

Endometriosis can affect any female who is having menstrual periods, but certain risks factors make it more likely for someone to develop endometriosis: having uterine abnormalities; not having a child before age 30; frequently experiencing longer menstrual periods (more than seven days) and shorter menstrual cycles (fewer than 25 days); and having a family history of endometriosis in a first-degree relative (mother, sister, daughter).


Scientists don't know the root cause of endometriosis, but there are several theories as to why some women develop it. Research indicates an environmental link between endometriosis and exposure to agents such as a chemical. A 2013 study from the Fred Hutchinson Cancer Research Center indicated exposure to certain pesticides, particularly organochlorine pesticides from landscaping and lawn care, increases risk for development of endometriosis by 30 to 70 percent. Fortunately, such pesticides are no longer in use in the United States.

Genetics are also thought to play a role through a gene mutation that could be inherited. Although no specific genetic mutation has been identified, this would explain why women with a first-degree family history of endometriosis are at greater risk. Another theory indicates that retrograde menstrual flow may play a role, leading to menstrual tissue in the pelvis, which can then attach to the outside wall of the uterus or surrounding structures.

The presence of active endometriotic lesions in post-menopausal women and (rarely) cis-men adds to the complexity of understanding the origins of this disorder.


It is important to note that symptoms and their severity vary greatly among women with endometriosis. The most common symptom is chronic pelvic pain occurring around the time of menstruation. This pain may feel like severe menstrual cramping, causing abdominal and/or lower back pain. For some women, this severe pain may occur during sex. Additionally, women may experience a heavier than normal menstrual flow. If the endometrium has attached to adjacent structures, such as the intestines or bladder, then pain can occur with a bowel movement or urination, respectively. Other minor symptoms include fatigue, bloating, nausea, diarrhea and constipation.

The most common symptom is chronic pelvic pain occurring around the time of menstruation.

Sometimes, women have no symptoms and the diagnosis of endometriosis is made at the time of abdominal surgery or discovered after a woman has had difficulty becoming pregnant, as infertility can be a sign of endometriosis. It's important to remember that the intensity and/or frequency of symptoms you experience does not necessarily indicate the extent of your condition.

Endometriosis is sometimes confused with other conditions because the range of symptoms is similar to ovarian cysts and pelvic inflammatory disease (PID). Additionally, irregular bowel movements and cramping can look like irritable bowel syndrome (IBS), a disorder that often goes along with endometriosis, making diagnosis even more difficult.


If you are having any of the above symptoms, seeking an evaluation from a gynecologist or other healthcare provider is an important first step, because having a diagnosis allows you to move forward with treatment options. The evaluation begins with a complete medical history and physical, including a pelvic exam. Definitive diagnosis is made with a laparoscopy, a minor surgical procedure in which a doctor makes a small abdominal incision, through which a camera can be inserted and biopsies can be obtained. Additionally, there are other types of imaging (ultrasound, CT or computed tomography, MRI or magnetic resonance imaging) that healthcare providers may use if the woman's history seems highly likely for endometriosis. But the gold standard remains direct visualization by laparoscopy.


After a diagnosis of endometriosis is made, a careful review of treatment options, risks and benefits should be discussed with your healthcare provider. The extent of the disease, symptoms, tolerance of these symptoms, overall health and desire for future pregnancies are all factors that will need to be discussed when choosing the most appropriate treatment.

Mild symptoms are generally treated with pain medications, typically a nonsteroidal anti-inflammatory drug (NSAID). The most commonly used is ibuprofen, such as Advil or Motrin. Alternative remedies and lifestyle modifications, including massage and supplements, are helpful to many women.

For women experiencing mild to moderate symptoms, oral contraceptives can be used to prevent ovulation and decrease menstrual flow. Progesterone is commonly given to significantly decrease menstrual flow and reduce symptoms. Hormonal medications help slow the growth of endometrial tissue. Other medications, called gonadotropin-releasing hormone agonists, can actually produce medical menopause. This will significantly slow or stop the growth of endometriosis. These medications can cause side effects similar to symptoms of menopause: hot flashes, headaches, difficulty sleeping or even bone loss. Women who have opted for this type of treatment may take a low-dose form of estrogen or progesterone to decrease these symptoms. This is called add-back therapy, and does not undo the positive effect of the medication.

Statistically, about 50 percent of infertile women are found to have endometriosis.

If medications are not helpful or well-tolerated or more definitive treatment is desired, surgical management is another option. Surgery is generally performed laparoscopically by either destroying or cutting out any visible lesions. Surgical management may improve future fertility and is often the preferred treatment method in women who want to get pregnant relatively soon as most of the medication-based approaches have a contraceptive effect.  Though surgery provides a more definitive treatment of endometriosis it is not necessarily curative and 40 to 50 percent of women will have a recurrence of pain within five years.

For some women, a hysterectomy—removal of the uterus and possibly the ovaries—may be the best option, though this is generally considered a last resort. Endometriosis usually improves after menopause for most women because the menstrual cycle has stopped, which stops most of the estrogen production and robs endometriosis of its means of stimulation. 

Menopause does not stop whole body estrogen production. The ovaries stop producing estrogen but there are extra-ovarian sites of estrogen production such as fat tissue. This may be why endometriosis continues to be an issue after menopause for some women.

All of these options should be thoroughly discussed with your doctor before moving forward with treatment.

Infertility and endometriosis

Statistically, about 50 percent of infertile women are found to have endometriosis. Research is ongoing to better understand this connection. Some studies indicate that the inflammation associated with endometriosis may lead to difficulty in the movement of the egg or sperm. Other studies suggest that endometriosis can affect the uterus in a way that harms the egg. Additionally, the inflammation caused by the disease may lead to scar tissue in the fallopian tubes, leading to blockage of the movement of the egg from the ovaries to the uterus.

Treatment with hormonal therapy will improve the symptoms of endometriosis but will not address the associated infertility. Surgical options are available for women having difficulty getting pregnant, however. The scar tissue can be surgically removed along with any endometriotic cysts. Another option often considered is IVF, or in vitro fertilization. In this procedure, an egg and sperm are obtained and combined in a laboratory setting and then implanted into the woman's uterus.

It's always important to discuss your fertility concerns with your healthcare provider. While women with endometriosis do face an increased infertility risk, having a healthy pregnancy is still possible for many women.


At this time, there is no known prevention for endometriosis. While some birth control methods can slow the progress of the disease, there is no way to fully stop the condition. Higher levels of awareness about endometriosis can help women get diagnosed earlier and learn to manage the long-term burden of painful symptoms.


If you suffer from endometriosis, there is comfort to be found in your community. Millions of American women are affected by this disease, and online and local support groups and forums will allow you to connect with others who know exactly what you are going through. You can also reach out to family and friends and educate them about endometriosis. And, of course, communicate with your partner about your symptoms and what you need from them when you're experiencing pain.

While the medical community may not fully understand the causes of endometriosis and how to prevent it, we do know that women who are diagnosed and treated for the disease benefit from improved outcomes and lessened discomfort. See a doctor if you experience symptoms, and tell your friends to do the same. Sharing information is critical in the battle against a disease with which so few people are familiar.

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A woman looks at a tablet with a doctor speaking on it.