Around 6 to 10 percent of people assigned female at birth (AFAB) are diagnosed with endometriosis—a chronic (long-term) condition that can cause pelvic pain and impact fertility. The disease occurs in people during their reproductive years (between their first menstrual period and menopause), but it most commonly affects people AFAB in their 30s and 40s.
Explore the causes, symptoms, and risk factors for the disease. Also, find out how the condition is diagnosed and which endometriosis treatments can help ease symptoms.
What is endometriosis?
The tissue that lines the inside of the uterus—the hollow female reproductive organ where a fetus develops—is called endometrium. The body produces new endometrium every menstrual cycle to prepare for a fertilized egg.
Endometriosis occurs when tissue similar to endometrium grows outside of the uterus. Healthcare providers (HCPs) sometimes refer to this displaced endometrial tissue as implants or lesions.
In most cases of endometriosis, endometrial tissue grows in the pelvic cavity, including on or around the:
- Fallopian tubes
- Surface of the uterus
- Ligaments around the uterus
- Lining of the pelvic cavity
- Area between the uterus and bladder or rectum
Endometrial tissue may also grow on the vagina, vulva, cervix, bowels, or bladder. Although uncommon, endometriosis can occur in parts of the body outside of the pelvic cavity and abdomen, including the lungs and skin.
What are the symptoms of endometriosis?
The most common symptom of endometriosis is pelvic pain, or pain in the lower abdominal area. This pain can be intense and often occurs just before or during menstrual periods, causing discomfort that’s described as significantly worse than typical period cramps. Period pain related to endometriosis or other factors is known as dysmenorrhea.
In addition to pelvic pain and uncomfortable periods, endometriosis symptoms may also include:
- Pain during or after sexual intercourse
- Bleeding or spotting between periods
- Unusually heavy or long periods
- Pain while urinating or during bowel movements
- Difficulty getting pregnant (infertility)
- Pain around the lower back or upper abdominal area
Other possible symptoms of endometriosis include constipation, diarrhea, nausea, bloating, gas, and fatigue. Digestive symptoms are particularly common in people with bowel endometriosis, which occurs when implants grow in or around the intestines, rectum, or other parts of the bowel.
When endometrial tissue forms around the lungs—a rare condition called thoracic endometriosis—symptoms like chest pain, labored breathing, or cough may occur during menstruation. Cutaneous endometriosis, which develops when endometrial lesions form on the skin, can cause firm, discolored skin nodules or lumps with pain or swelling that also corresponds with a person’s menstrual cycle.
Endometriosis vs. period pain
It can be difficult to differentiate endometriosis from period pain, especially since endometriosis pain tends to worsen during menstruation. But endometriosis can cause symptoms that generally aren’t associated with periods, such as:
- Pain during sexual intercourse, bowel movements, or urination
- Pain that feels constant, as opposed to menstrual cramps that may come and go
- Pain that persists after your period is over
- Intense pain that can make it difficult to perform everyday tasks
Endometriosis pain and period pain also have different causes. Menstrual cramps occur when hormone-like substances called prostaglandins trigger the uterus to contract and shed its lining, which can result in lower abdominal pain. Pain related to endometriosis, on the other hand, is linked to inflammation caused by the growth of endometrial tissue outside of the uterus. Endometriosis may also lead to scar tissue formation, which can contribute to pain.
Diseases with similar symptoms
Endometriosis is one of several conditions that can cause pelvic pain in people AFAB. Endometriosis is sometimes mistaken for ovarian cysts or pelvic inflammatory disease (PID), an infection in the female reproductive tract.
Irritable bowel syndrome (IBS), like endometriosis, can cause bloating, constipation, nausea, and diarrhea. While these conditions are separate, IBS is known to accompany endometriosis in some cases. A 2022 review and analysis of studies published in Frontiers in Medicine found that people AFAB with endometriosis are nearly three times more likely to develop IBS than those without it. Of the more than 96,000 participants included in the analysis, approximately one in four participants with endometriosis had IBS.
The only way to determine what’s causing your symptoms and to find appropriate treatment is to speak with an HCP. They can talk with you about your medical history, discuss your symptoms, and perform a physical exam to help diagnose your condition.
What causes endometriosis?
The causes of endometriosis aren’t fully understood. Researchers believe multiple factors can play a role in the development of the condition, including:
Retrograde menstruation: The suspected root cause of many endometriosis cases, retrograde menstruation occurs when cells from endometrial tissue that has shed flow backwards into the fallopian tubes and pelvic cavity instead of exiting the body during menstruation.
Cellular metaplasia: It’s possible for cells located outside of the uterus to undergo changes and transform into endometrial cells.
Lymph system or blood transport: In a way similar to how cancer cells may travel from one area of the body to another, endometrial cells may be carried to other parts of the body through blood or the lymphatic system. The lymphatic system is a major part of the immune system composed of various organs and lymph nodes, ducts, and vessels that produce and move lymph fluid from tissues to the bloodstream.
Immune system disorders: Research suggests a possible connection between endometriosis and certain autoimmune diseases, such as rheumatoid arthritis, Sjogren’s syndrome, and lupus. A problem with the immune system may allow endometrial tissue to grow outside of the uterus instead of being recognized as abnormal and destroyed by the body.
Hormonal problems: There’s a link between endometriosis and the hormone estrogen. Problems that lead to high estrogen levels may contribute to endometriosis, although more research on this subject is needed.
What are the risk factors of endometriosis?
Endometriosis affects people who are born with a uterus. While the precise cause of endometriosis is unclear, experts have found several factors that can increase a person’s risk.
Anyone with a menstrual cycle can develop endometriosis, including teenagers. Still, it most often affects people in their 30s and 40s.
Endometriosis may have a genetic basis. You’re more likely to have endometriosis if your biological parent, sibling, or child has been diagnosed with it.
People who have never given birth have a higher risk of endometriosis than those who have.
There’s a connection between the details of your menstrual history and your risk of endometriosis. For instance, you’re more likely to have endometriosis if:
- You started your period before age 11
- Your menstrual cycles are typically short (less than 27 days on average)
- Your periods tend to be heavy or last longer than seven days
It’s important to remember that having one or more endometriosis risk factors doesn’t mean you’re certain to develop the condition. On the other hand, it’s possible to have endometriosis without any known risk factors.
What are the stages of endometriosis?
There are four general stages of endometriosis, which are based on the location and extent of the endometrial implants as well as how deep the implants have grown into other tissue.
Stage 1: Minimal
Stage 1 endometriosis involves a few superficial implants. Most people with endometriosis have stage 1 or 2 disease.
Stage 2: Mild
In stage 2 endometriosis, endometrial implants increase in number and depth.
Stage 3: Moderate
Stage 3 endometriosis involves multiple deep implants. Small endometriomas—cysts that are a byproduct of endometriosis—are present on one or both ovaries. (Cysts are fluid-filled growths that are usually noncancerous.) Endometriomas contain dark brown endometrial fluid and are sometimes called chocolate cysts.
Bands of scar tissue known as adhesions are also present in stage 3 endometriosis. Adhesions can bind surrounding organs together. In this stage, adhesions may be thin and filmy.
Stage 4: Severe
Stage 4 endometriosis is characterized by multiple deep implants. There are large endometriomas on one or both ovaries, along with several dense adhesions. People with stage 4 endometriosis are likely to experience infertility.
Unlike many other conditions, endometriosis stages don’t necessarily correlate with the presence or severity of symptoms. Someone can have stage 3 endometriosis and experience little to no pain, while stage 1 endometriosis may cause debilitating symptoms.
How is endometriosis diagnosed?
Endometriosis is often diagnosed in people who seek medical attention for painful periods or difficulty getting pregnant. In other cases, it’s discovered during testing or surgery for another issue.
That said, there’s sometimes a delay in diagnosing endometriosis. This is because many people AFAB typically experience uncomfortable periods, and more common explanations for pelvic pain (such as urinary tract infections or ovarian cysts) are often considered before endometriosis.
An HCP will go over your personal and family medical history, discuss your symptoms, and perform a physical exam. If necessary, they’ll perform or order several tests to determine what’s causing your symptoms. You may be referred to an HCP who specializes in diagnosing and treating diseases of the female reproductive system, such as a gynecologist, for more specialized care.
Review of medical history
Diagnosing endometriosis usually begins with a detailed review of your personal and family medical history. You may be asked about:
- The timing and severity of your symptoms
- The location of your pain
- Your menstrual cycle
- Previous pregnancies, surgeries, or health issues
- The health of first-degree blood relatives (such as parents or siblings), including if they have endometriosis or other reproductive health issues
The next step is usually a pelvic exam, during which your HCP will feel for abnormalities around your uterus and ovaries. Signs of stage 1 and 2 endometriomas are difficult to detect through a pelvic exam, so imaging tests of the pelvic area are typically recommended.
Ultrasound imaging uses high-frequency sound waves to produce images of the reproductive organs and to check for signs of endometriosis and other reproductive health concerns. Your HCP may recommend an abdominal ultrasound, during which a device called a transducer is gently pressed against the abdominal area, or a transvaginal ultrasound, which involves inserting a small transducer wand into the vagina.
Magnetic resonance imaging (MRI)
An MRI scan is particularly helpful in evaluating the location and size of endometrial lesions. This imaging test uses radio waves and a magnetic field to create detailed pictures of the pelvic organs and tissues.
Laparoscopic surgery is the only definitive way to diagnose endometriosis, although other test results help confirm the diagnosis. During laparoscopy, a surgeon inserts a laparoscope—a thin, lighted instrument with a small camera on the end—into the pelvic cavity through a tiny incision in your naval area. This allows the surgeon to check for displaced endometrial tissue. You’ll be placed under general anesthesia for this procedure.
A laparoscope may also be used to collect a small sample of tissue, which can be tested for endometrial cells underneath a microscope, a procedure called a biopsy. In some cases, all displaced endometrial tissue can be removed during the procedure to treat the condition.
What are the possible complications of endometriosis?
Untreated endometriosis can lead to complications like chronic pain and digestive issues. The most common complication of endometriosis, however, is infertility.
Endometriosis is among the leading causes of infertility. But the relationship goes both ways.
Between 20 and 50 percent of people AFAB who experience infertility have endometriosis, while 30 to 50 percent of those AFAB who have endometriosis experience infertility.
There are a few ways endometriosis contributes to infertility. Endometrial implants may lead to the production of molecules called cytokines that cause inflammation, which can essentially paralyze a sperm and egg and prevent fertilization. Endometriosis-related inflammation also alters pelvic anatomy by creating adhesions and endometriomas, which can block the ovaries and fallopian tubes and disrupt the ovulation and fertilization processes.
The good news is that many people with infertility related to endometriosis can become pregnant and carry a pregnancy to term with appropriate treatment. Surgery to remove endometrial tissue from the pelvic area can help some people conceive. In other cases, surgery may be combined with fertility treatments such as:
- In-vitro fertilization (IVF): IVF treatment involves combining sperm and egg in a laboratory, then placing the fertilized egg (called an embryo) directly into the uterus.
- Intrauterine insemination (IUI): During an IUI procedure, collected sperm is placed directly into the uterus with a long, narrow tube.
- Third-party assisted reproductive technology (ART) methods: This includes surrogacy, egg donation, embryo donation, and sperm donation.
If you have endometriosis and are hoping to become pregnant in the future, it’s important not to delay treatment. Endometriosis can worsen and become more difficult to treat as years go by.
Despite a popular notion that endometriosis increases ovarian cancer risk, only a small amount of evidence suggests this is true. Rare cancers like endometrioid ovarian cancer and clear cell ovarian cancer are more common in people with endometriosis, but the risk of developing these diseases is still lower than 1 percent. There’s evidence that links endometriosis to an increased risk of thyroid cancer, although more research on this subject is needed.
What happens if endometriosis is left untreated?
Untreated endometriosis may never cause a problem for some people. For others, it can lead to debilitating pain and infertility. Endometriosis symptoms vary from person to person, as do the long-term effects of the condition.
Endometriosis symptoms improve for most people when they go through menopause. This is a result of the hormonal changes that occur once a person stops getting a period.
When should you see a doctor?
You should speak with an HCP if you notice any changes in your menstrual cycle or possible symptoms of endometriosis, such as lower abdominal pain, unusually heavy or uncomfortable periods, and painful sex. An HCP can identify the cause of your symptoms and work with you on a treatment plan to manage them effectively.
How is endometriosis treated?
Your best course of endometriosis treatment will depend on factors such as your age, symptoms, other health conditions you might have, treatment preferences, and if you want to become pregnant in the future. Common treatment approaches for endometriosis include:
Over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen sodium can help ease endometriosis and period pain. NSAIDs help reduce inflammation and pain by blocking the release of prostaglandins.
It’s best to start taking these pain relievers one to two days before your period starts to prevent prostaglandin production. But be sure to talk with your HCP about which NSAID is best for your endometriosis symptoms. In some cases, this may include taking a prescription-strength NSAID if the OTC dose doesn’t relieve your pain.
Hormones influence endometrial tissue both inside and outside of the uterus, which is why endometriosis pain tends to worsen during your period. Hormone therapy can help control endometriosis symptoms by changing hormone levels or stopping your body from creating certain hormones. However, hormone therapy is not a good option for people who are pregnant or trying to conceive.
There are multiple types of hormone therapies, including:
Hormonal contraceptives—better known as hormonal birth control—suppress the hormones responsible for producing endometrial tissue using progesterone or a combination of estrogen and progesterone. Birth control comes in many forms, including pills, patches, vaginal rings, shots, and intrauterine devices (IUDs).
Taking birth control can significantly reduce or eliminate endometriosis pain in many cases. It may also result in shorter, lighter periods.
Progestin—a synthetic form of the hormone progesterone—works to treat endometriosis by pausing menstrual cycles and hindering the growth of endometrial implants. Another form of hormonal birth control, progestin may be recommended if therapies containing estrogen aren’t recommended or don’t provide adequate pain relief. Progestin therapies are available as a pill (norethindrone), injection (medroxyprogesterone), implant (etonogestrel), and intrauterine device (levonorgestrel).
Gonadotropin-releasing hormone (GnRH) analogs
This type of medication includes gonadotropin-releasing hormone agonists and antagonists. Both drugs work by temporarily pausing estrogen production in the ovaries, which can help shrink endometrial implants and relieve pain. GnRH agonists include nafarelin (a nasal spray), and leuprolide and goserelin (which come in the form of shots). Elagolix and relugolix are antagonists that are available in pill form.
Danazol is a hormone therapy capsule that shrinks endometrial implants and stops the menstrual cycle, although it’s still possible to occasionally get a period while on the medication. This therapy isn’t widely used due to its androgenic side effects, which pertain to male characteristics. These may include weight gain, increased sweating, oily skin, and decreased breast size.
An aromatase inhibitor is a type of medication that lowers estrogen levels in the body. It’s often prescribed in combination with a hormonal contraceptive.
Minimally invasive endometriosis surgery
A laparoscopy is a minimally invasive endometriosis surgery that can be used to diagnose the condition and remove abnormal tissue. Also known as keyhole surgery, this procedure may be recommended if you’re trying to get pregnant or if your symptoms don’t improve with medication.
A laparoscopy is done under general anesthesia and performed with a long, thin tube equipped with a light and video camera called a laparoscope. During the procedure, a surgeon makes a few small incisions around the abdomen to accommodate the laparoscope and specialized instruments that remove endometrial implants, endometriomas, and scar tissue or that destroy these abnormal tissues with heat (a process known as ablation).
Robotic-assisted technology may also be used to provide the surgeon with detailed, 3D views of the pelvic cavity. In this case, the surgeon uses computer-controlled robotic arms to perform the procedure, which allows for greater range of motion and precision than the human hand alone can accomplish.
Laparoscopy is a viable treatment option for some people with endometriosis-related infertility. Around 75 percent of people who have this endometriosis surgery also have less pain for a few months after the procedure.
Remember that any surgery—including minimally invasive endometriosis surgery—comes with some measure of risk. Endometriosis is a chronic, lifelong condition, which means abnormal tissue growth may occur again and symptoms may return even after surgery. Your HCP will likely encourage you to continue with some form of endometriosis treatment (such as hormone therapy) to lower the risk of this happening.
Hysterectomy is generally viewed as a last resort surgery for advanced cases of endometriosis. This procedure involves removing the entire uterus and surrounding endometrial implants, sometimes along with the ovaries and other reproductive organs. A hysterectomy may be necessary to address severe endometriosis with implants between the uterus and rectum, although this type of the condition is uncommon.
There are multiple approaches to hysterectomy, and your HCP can help determine which one is best for you based on your age, symptoms, and treatment preferences. Types of hysterectomies that may be performed to treat endometriosis include:
- Total hysterectomy: The uterus and cervix are removed.
- Hysterectomy with bilateral salpingo-oophorectomy: The uterus, both ovaries, and both fallopian tubes are removed. A hysterectomy with a unilateral salpingo-oophorectomy involves removing the uterus and just one ovary and fallopian tube.
- Supracervical hysterectomy: The body of the uterus is removed, but the cervix is kept in place.
Removing the uterus and ovaries can effectively treat endometriosis. But you should carefully weigh all your options before undergoing a hysterectomy or oophorectomy. You won’t be able to become pregnant after a hysterectomy, and an oophorectomy will put you into menopause, no matter your age. Possible symptoms of menopause include hot flashes, loss of bone density, decreased sexual desire, and mood changes.
Can you prevent endometriosis?
Endometriosis can’t be prevented, but there are certain factors that may lower your risk. These include:
- Staying at a healthy weight
If you had your first menstrual period after age 11, you may also have a lower risk of endometriosis than people who started menstruating at a younger age. Talk to your HCP about your individual risk for endometriosis and how you may help preserve your reproductive health.
What is the outlook for endometriosis?
There’s no cure for endometriosis, but treatment can help you manage your symptoms and live more comfortably. Some people with endometriosis never experience pain or fertility issues. After menopause, endometriosis is unlikely to cause disruptive symptoms or complications.
Can endometriosis go away on its own?
It’s possible for endometriosis to go away on its own. Endometriosis symptoms tend to diminish after menopause when estrogen levels in the body dip. In other cases, implants may simply shrink as years go by.
Still, endometriosis usually persists or worsens with time in people who haven’t reached menopause. It’s always a good idea to speak with your HCP if symptoms related to your endometriosis or menstrual cycle worsen.
Living with endometriosis
Endometriosis symptoms like uncomfortable periods, infertility, and painful sex can have a profound impact on your relationships and emotional health. If left unaddressed, chronic pain can make it difficult to go to work, attend school, or participate in activities you once enjoyed. Finding the right care options for your needs can help you overcome your physical and emotional symptoms and improve your overall well-being.
Some people find it beneficial to join online or in-person endometriosis support groups in addition to receiving clinical treatment. Self-care measures like engaging in regular exercise to ease endometriosis symptoms, incorporating stress-relieving techniques like meditation and journaling into your daily routine, and taking relaxing, warm baths to ease pain can also be helpful.
If you have endometriosis, it’s important to take steps to manage your condition and reach out for help when you need it. Your HCP can suggest ways to better control your symptoms and refer you to a licensed mental health provider, if you’d like. With the right treatment and support, you can enjoy an active and healthy life with endometriosis.
Featured endometriosis articles
Adesanya OA, Kolawole OE. Thoracic endometriosis syndrome: Cutting the gordian knot—A case report and review of the literature. Int J Surg Case Rep. 2020;66:68-71.
Chiaffarino F, Cipriani S, Ricci E, Mauri PA, Esposito G, Barretta M, Vercellini P, Parazzini F. Endometriosis and irritable bowel syndrome: A[LF1] systematic review and meta-analysis. Arch Gynecol Obstet. 2021 Jan;303(1):17-25.
Cleveland Clinic. Endometriosis. Last reviewed July 27, 2022.
Endometriosis Foundation of America. Endometriosis Stages: Understanding the Different Stages of Endometriosis. Accessed May 8, 2023.
Eunice Kennedy Shriver National Institute of Child Health and Human Development. About Endometriosis. Last reviewed February 21, 2020.
Harvard Health Publishing. Does Endometriosis Increase Cancer Risk? Published May 1, 2019.
Hoyle AT, Puckett Y. Endometrioma. [Updated 2022 Jun 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
John Hopkins Medicine. Endometriosis. Accessed May 5, 2023.
John Hopkins Medicine. Period Pain: Could it Be Endometriosis? Accessed May 17, 2023.
Kvaskoff M, Mahamat-Saleh Y, Farland LV, et al. Endometriosis and cancer: a systematic review and meta-analysis. Hum Reprod Update. 2021;27(2):393-420.
Liu JH. Endometriosis. Last updated September 2022.
Mayo Clinic. Endometriosis. Last updated July 24, 2018.
MedlinePlus. Endometriosis. National Library of Medicine. Last updated March 7, 2022.
Mount Sinai. Endometriosis. Last reviewed January 10, 2022.
Nabi MY, Nauhria S, Reel M, et al. Endometriosis and irritable bowel syndrome: A systematic review and meta-analyses. Front Med (Lausanne). 2022;9:914356.
NYU Langone Health. Surgical Treatment for Endometriosis. Accessed May 9, 2023.
Office on Women’s Health. Endometriosis. Last updated February 22, 2021.
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Rzewuska AM, Żybowska M, Sajkiewicz I, Spiechowicz I, Żak K, Abramiuk M, Kułak K, Tarkowski R. Gonadotropin-Releasing Hormone Antagonists—A New Hope in Endometriosis Treatment? Journal of Clinical Medicine. 2023; 12(3):1008.
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[LF1]Aloha Jordan - AMA style requires capitalizing the first letter following a colon, semicolon, em dash, en dash, etc.
[LF2]Modified this to comply with AMA style. Author’s name includes last name and initial(s) only. Their title or degree info isn’t included. Also, the name of the organization publishing the article (i.e., Mass Gen Hospital) is listed after the article title.
[LF3]Don’t forget the title of the journal article should be in sentence case, although the first letter following a colon, semicolon, or em or en dash are capitalized (as mentioned in my comment above). PubMed and other medical databases don’t always get the AMA-style casing right. Therefore, we have to correct the formatting as needed.