Endometriosis is a painful, chronic disease affecting at least 10 to 15% of all women. It occurs when endometrial tissue grows outside the uterus, leading to problems such as ovarian cysts, infertility, and even cancer.¹ Endometriosis is chronically underreported, likely because it’s difficult and expensive to diagnose.² However, early treatment is critical for adequate prevention and treatment.
While no conclusive causes of endometriosis have yet been discovered, we’ll cover the risk factors and possible explanations from medical experts. Currently, there is no cure for endometriosis, but there are effective treatments for its symptoms. Read on to find out more about endometriosis: what it is, how it works, what you can do about it, and ways you can connect with others to find support or support those in your life who have it.
Endometriosis is a chronic disease in which endometrial tissue (the tissue lining the uterus) grows outside the uterine cavity.¹ During a menstrual cycle, the endometrium thickens, sloughs, and eventually exits the body through the vaginal canal in the form of menstrual blood, which is made up of endometrial cells, blood, and vaginal discharge.³ Endometrial tissue growing outside the uterus behaves like endometrial tissue within the uterus, thickening, sloughing, and shedding according to the same hormonal fluctuations.⁴ This can, understandably, cause problems when there’s nowhere for the blood to go.
Areas in the body where endometriosis commonly develops include the following:⁵
Endometriosis can also develop in the following areas:⁵
Complications arise when the tissue grows in an area in the body with no access to the vaginal canal. It can get trapped, causing pain, ovarian cysts called endometriomas, inflammation, scar tissue, and even infertility. People with endometriosis also have an increased risk of developing ovarian cancer, as well as a rare cancer called endometriosis-associated adenocarcinoma.¹
Though the causes of endometriosis remain unknown, several theories explain why endometriosis occurs. We’ll cover the biggest ideas posed by medical experts. Any number of the following situations may cause endometriosis.
Endometriosis often runs in families: if you have an aunt, grandmother, or mother with endometriosis, you’re more likely to have it. If endometriosis is inheritable through your genes, that may be why it’s seen more strongly in certain families than others.⁵ More research is needed to state whether endometriosis has a genetic component conclusively.
Retrograde menstruation occurs when menstrual blood flows back into the body through the fallopian tubes instead of exiting through the vaginal canal. Since menstrual blood contains endometrial cells, the cells may implant in areas inside the pelvis, such as the walls and organs, and continue to grow and respond to hormonal changes during each menstrual cycle.¹
Sometimes, hormonal changes or immune system disorders can transform cells of a certain type into another. For example, estrogen can sometimes transform new cells into endometrial cells. If the immune system doesn't recognize endometrial tissue growing outside the uterus and fails to destroy it, the tissue will continue to develop, causing endometriosis.¹
During a surgery such as a hysterectomy or C-section, endometrial cells might be unintentionally transplanted to another area of the body, such as the abdomen.⁶
Like the way cancer cells are spread, endometrial cells could be picked up by the blood or lymphatic systems and carried to other areas of the body, where they can implant and grow.⁵
Staying aware of potential risk factors can help you and your doctor detect endometriosis early and manage your chance of developing severe symptoms or complications. However, having one or more risk factors does not mean you have endometriosis. If you are experiencing symptoms of endometriosis, consult with your physician for a proper diagnosis and referral to a specialist.
The biggest risk factors of endometriosis are:
Endometriosis affects 10 to 15% of all women between the ages of 15 and 44.⁵ While it is most common in women in their 30s and 40s, many women report endometriosis symptoms in adolescence.⁶ The late age of onset may actually be because it often takes years (and, in some cases, decades) to get a formal diagnosis.
If you have one or more of the following symptoms, it is important to consult with a physician for a proper diagnosis. It’s important to note that every person’s experience with endometriosis is unique, and having one or more of these symptoms does not necessarily mean you have it.
Pain is the most commonly reported symptom and is, unfortunately, a hallmark of endometriosis. The pain can range from moderate to severe, affecting your quality of life and daily functioning. People with endometriosis can experience any or all of the following:
Pelvic pain, in particular, is a giant red flag. It’s so common that researchers have found that 70% of women with chronic pelvic pain have endometriosis.² While pain is the most common symptom, people can also experience:
For many women, the most concerning symptom of endometriosis is infertility. This relationship goes both ways: many women discover they have endometriosis when they first seek treatment for their infertility. According to the American Society of Reproductive Medicine, 24-50% of women who experience infertility have endometriosis.⁵ Other research shows that a similar proportion of women with endometriosis experience difficulty conceiving (between 33% and 50%).²
Infertility due to endometriosis can range from mild to severe, with temporary difficulties conceiving and longer-term sterility possible. The causes of endometriosis-induced infertility remain unclear, but some explanations medical experts think may cause it include:
Fortunately, infertility caused by endometriosis is typically treatable. Women can often conceive and carry babies to term with fertility treatments such as IVF (in vitro fertilization) and fertility preservation.⁸ Because endometriosis can worsen over time, it is recommended to begin treatment as soon as possible.¹
Endometriosis can be difficult to diagnose. The symptoms of endometriosis vary greatly from person to person, and they can resemble other diseases such as pelvic inflammatory disease (PID) or irritable bowel syndrome (IBS). Sometimes there are no symptoms besides infertility, and endometriosis is discovered during fertility treatments.¹
Additionally, there is often a delay in diagnosis due to underreporting and the high cost of diagnosis and treatment. According to one study, the average delay between symptom onset and diagnosis is 6.7 years.²
If you and your doctor suspect you might have endometriosis, your doctor will ask you about your medical history and the location and frequency of your symptoms. They’ll then use either nonsurgical or surgical methods to diagnose you. Many people with endometriosis will need a surgical procedure for a formal diagnosis.
It’s rare to diagnose endometriosis without surgery. However, doctors can use many nonsurgical methods to get an idea of what’s going on.
Doctors may first perform a pelvic exam, using their hands to feel the pelvic area for abnormalities. Sometimes endometriosis may cause cysts, called endometriomas, which doctors can manually feel.⁹ The doctor may also choose to examine the vagina, vulva, cervix, and rectum during this exam to ensure you don’t have other problems with similar symptoms.
Transvaginal and abdominal ultrasounds are also commonly used to diagnose endometriosis. During these ultrasounds, doctors may look for more evidence of endometriomas that might be too small or deep to be felt externally.
If ultrasounds are inconclusive, an MRI can give doctors a better, more detailed view of the parts of your body that might be affected by endometriosis. This is also helpful for surgeons as they can have a clearer image of the size and location of endometrial tissue.⁹
Once doctors have exhausted nonsurgical measures — or suspect that endometriosis is present — they may move on to more invasive methods to conclusively diagnose endometriosis. Most often, they will start with a laparoscopy.
A laparoscopy is a surgical procedure done by making a small incision close to the navel and inserting a small instrument with a camera to look for endometrial tissue outside the uterus. If they find endometrial tissue, the surgeon typically removes a tissue sample to study it further and confirm the diagnosis (a biopsy).⁹ In some cases, they'll remove as much of the tissue as possible at this stage to minimize your chances of needing more surgeries later on.
Like your diagnostic options, you can choose between noninvasive (medication) or surgical treatment for endometriosis. Your treatment options depend on the severity of your symptoms, the extent of endometriosis, and whether you want to be pregnant later in life. Typically, doctors will start with a noninvasive treatment, such as pain management or hormone therapy, before resorting to surgeries.
Below, we’ll dig deeper into your treatment options.
Because of the tremendous impact endometriosis pain can have on your daily functioning and quality of life, it is usually the first thing doctors will address. This includes over-the-counter pain medications, which are typically nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or Aleve (naproxen sodium). If the pain is severe, the doctor may prescribe prescription painkillers.
Hormonal therapy can be used with pain medication, particularly if you don’t want to be pregnant. Because endometriosis responds to the same hormonal fluctuations as the menstrual cycle, hormonal therapy can effectively control symptoms such as pain and bleeding. It may even slow the progression of endometriosis by inhibiting new endometrial tissue growth and preventing endometrial tissue implants. However, while it is effective, it is not permanent. Once hormonal therapy is halted or stopped, the symptoms may return.⁹
Depending on your symptoms, medical history, and needs, there are a few different kinds of hormonal therapy your doctor may prescribe.
Doctors may prescribe intrauterine devices, injections, or implants that deliver the hormone progestin. Progestin can effectively stop the growth of endometrial tissue by suppressing the menstrual cycle.⁹
This type of medicine is used to reduce the female hormone estrogen. Lowering your estrogen levels inhibits endometrial tissue growth and reduces inflammation. Aromatase inhibitors are typically prescribed in combination with another hormonal therapy.⁹
Birth control pills or patches effectively treat or even eliminate pain from endometriosis by controlling hormones and regulating or lightening menstrual cycles.⁹
You may also be prescribed gonadotropin-releasing hormone (GnRH) agonists and antagonists. GnRH agonists and antagonists target ovarian hormones and are used to treat a variety of illnesses.
Gonadotropin-releasing hormone is a reproductive hormone that works with the brain’s pituitary gland to stimulate ovulation. If the GnRH is released slowly, the brain releases a follicle-stimulating hormone (FSH), which tells an egg to develop. If GnRH is released in quick waves, the brain releases luteinizing hormone (LH), which causes ovulation.¹⁰ GnRH agonist drugs prevent an LH hormone surge by desensitizing the pituitary gland and slowing the release of GnRH over time. GnRH antagonists block GnRH much faster, usually within a few hours.¹¹
These drugs stop menstruation and lower estrogen levels. Because of this, you’ll go into an artificial state of menopause, and you might need further medication to reduce the side effects. Like hormonal birth control, stopping GnRH drugs causes menstrual cycles and ovulation to resume.⁹
If pain management and hormonal therapy aren’t enough to quell your symptoms or the endometriosis becomes severe, you may need surgical treatment. When laparoscopy is done to determine whether endometrial tissue is present outside the uterus, surgeons will often remove the endometrial tissue they find to limit the number of surgeries you’ll need over time. Because of this dual diagnosis-treatment approach, it’s the most common surgical procedure used to treat endometriosis. However, because endometrial tissue can grow back, it may not be a permanent fix as symptoms may return.⁵
If the endometriosis has progressed or is more severe, more invasive surgery may be necessary. Similar to laparoscopy, a laparotomy uses a larger incision in the abdomen to remove extensive endometrial tissue. Like laparoscopy, laparotomy may also not be a permanent solution.⁵
The most intense treatment for endometriosis is the complete removal of the uterus and ovaries. A hysterectomy refers to the surgical removal of the uterus. Combined with an oophorectomy (surgical removal of the ovaries), these surgeries were once the go-to treatment for endometriosis. However, many complications can arise from such an invasive surgery, and doctors are now more reluctant to recommend it.
Although ovarian removal can effectively relieve symptoms caused by endometriosis, it also results in menopause. Early menopause carries with it the risk of:
If only the ovaries are removed (oophorectomy), you could still get pregnant through IVF. However, if you have a hysterectomy, you won’t be able to get pregnant. The decision to have a hysterectomy or oophorectomy as treatment of endometriosis is one that must be made with careful consideration of the patient's health, wishes regarding pregnancy, and the severity of the disease and its symptoms.⁹ Like the other treatments, even major surgeries such as hysterectomies and oophorectomies cannot guarantee permanent relief from endometriosis. If any endometrial tissue is left behind, it can still cause problems.⁹
Endometriosis is a chronic disease that requires regular monitoring, even after treatment. Any disease progression in its severity must be acted upon as soon as possible, particularly if fertility preservation is a goal. Timely diagnosis of the disease is critical as it can prevent many problems (such as pain, deep tissue implants, fallopian tube blockages, and adhesions) before they affect your quality of life. A combination of pain management, hormonal therapy, and surgery can effectively treat endometriosis symptoms.
Although there is no cure for endometriosis yet, there is no reason why someone with endometriosis cannot live a full and happy life. However, managing life with the disease can be difficult without the proper support and resources. There are many organizations that support people with endometriosis by connecting them with other patients and providing up-to-date research to healthcare providers about therapies and treatments. We’ve compiled a small list of these organizations below.
 Endometriosis - Symptoms and causes. (2018, July 24). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/endometriosis/symptoms-causes/syc-20354656
 Parasar, P., Ozcan, P., & Terry, K. L. (2017). Endometriosis: Epidemiology, Diagnosis and Clinical Management. Current Obstetrics and Gynecology Reports, 6(1), 34–41. https://doi.org/10.1007/s13669-017-0187-1
 Yang, H., Zhou, B., Prinz, M., & Siegel, D. (2012). Proteomic analysis of menstrual blood. Molecular & cellular proteomics: MCP, 11(10), 1024–1035. https://doi.org/10.1074/mcp.M112.018390
 Riverview Health. (2017, May 31). If It’s Endometriosis, Will You Know? https://riverview.org/blog/womens-health/if-its-endometriosis-will-you-know/
 Endometriosis. (n.d.). Johns Hopkins Medicine. Retrieved November 6, 2022, from https://www.hopkinsmedicine.org/health/conditions-and-diseases/endometriosis
 Endometriosis. (2021, March 31). https://www.who.int/news-room/fact-sheets/detail/endometriosis
 Endometriosis: Office on Women’s Health. (n.d.). https://www.womenshealth.gov/a-z-topics/endometriosis
 What is fertility preservation? Eunice Kennedy Shriver National Institute of Child Health and Human Development. (2017, January 31). https://www.nichd.nih.gov/health/topics/infertility/conditioninfo/fertilitypreservation
 Endometriosis - Diagnosis and treatment - Mayo Clinic. (2018, July 24). https://www.mayoclinic.org/diseases-conditions/endometriosis/diagnosis-treatment/drc-20354661
 GnRH antagonist vs GNRH agonist protocol: which patients does it benefit? (2020, June 14). Medivizor. https://medivizor.com/blog/SampleLibrary/infertility-reproductive-technologies/gnrh-antagonist-vs-gnrh-agonist-protocol-which-patients-does-it-benefit/
 Stimpfel, M., Vrtacnik-Bokal, E., Pozlep, B., & Virant-Klun, I. (2015). Comparison of GnRH agonist, GnRH antagonist, and GnRH antagonist mild protocol of controlled ovarian hyperstimulation in good prognosis patients. International journal of endocrinology, 2015, 385049. https://doi.org/10.1155/2015/385049