How Is Endometriosis Diagnosed?

Endometriosis occurs when cells that are similar to the tissue that lines the inside of the uterus—known as the endometrium—begin to grow outside of the uterus. Patches of this abnormal tissue growth, also known as lesions, can grow near your pelvic region, on your ovaries and fallopian tubes, or behind your uterus. Sometimes, lesions can spread to nearby organs, like your colon or bladder.

Lesions can cause a host of painful symptoms such as pelvic pain, cramps, infertility, and changes to your menstrual cycle. If you think you may have symptoms of endometriosis, it's good practice to visit your healthcare provider and discuss your symptoms.

During your appointment, your provider will take a thorough medical history and perform a pelvic exam. They may also order additional diagnostic measures such as blood tests, imaging scans, or a laparoscopy. The only way to confirm an endometriosis diagnosis is via laparoscopy—which is a minimally-invasive surgical procedure that checks for lesions in your pelvic and abdominal organs and removes the lesions to send them in for proper lab testing.

Medical History

At your visit with a healthcare provider (e.g., a primary care physician or gynecologist), your provider will ask about your symptoms, menstrual cycle, and personal and family medical history.

They may ask you questions like:

• What are your symptoms?
• How severe are your symptoms?
• Do symptoms keep you from engaging in your daily activities?
• How long have you been experiencing symptoms?
• Do symptoms worsen when you are on your period?
• On average, how many days is your menstrual cycle?
• How heavy are your periods?
• Does anyone in your family have a history of endometriosis?
• Have you experienced any concerns with infertility or trouble conceiving?

Pelvic Exam

After gathering information about your symptoms, your healthcare provider will perform a pelvic exam. This exam helps them check for signs of pressure or pain you're experiencing and look for any nodules or lumps that might be present in your pelvic area.

To perform a pelvic exam, your provider will wear clean gloves and use lubrication to insert one or two fingers into your vagina, anus, or both. They will then place their other hand on your lower abdomen. In some cases, a healthcare provider may use a speculum, which is a plastic or stainless steel medical device that helps open up your vagina. A speculum can also help your provider notice any structural changes to your vagina and cervix—which can occur due if you have scarring.

A pelvic exam is not the most reliable test for diagnosing endometriosis. Based on your symptoms and findings from the pelvic exam, your healthcare provider may suggest further testing to confirm a diagnosis for endometriosis.

Imaging Tests

Your healthcare provider can also use imaging tools to take detailed pictures of your pelvic region. A vaginal ultrasound and magnetic resonance imaging (MRI) are most useful in detecting large lesions. Keep in mind: small lesions may not show up in pictures, so additional testing may be necessary.

Here's what you can expect from both types of imaging tests:

• Ultrasound: Your provider will insert a thin device (known as a transducer) that is covered in gel into your vagina or pressed on top of your stomach. The ultrasound technology will use soundwaves to create pictures (or, sonograms) of your pelvic region. The images can show signs of a thick tissue lining, lesions, nodules, and cysts.
• MRI: Your healthcare provider may suggest an MRI if the results from the ultrasound are inconclusive—meaning there is not enough evidence to confirm or deny a diagnosis. An MRI uses radio waves to take detailed pictures of the inside of your body. In most cases, an MRI will only show deep infiltrating endometriosis (DIE), which causes lesions in the pelvic wall, on the bowels, the area between the uterus and rectum, and the bladder. DIE affects about 20% of people with endometriosis.
  

Laparoscopy

Currently, a laparoscopy is the only surgical procedure that can accurately diagnose and confirm endometriosis. A laparoscopy makes a small incision (cut) in the lower abdomen and inserts a laparoscope—a device with a light and small camera—to see the inside of the pelvic region. Typically, a gynecologist or surgeon will perform this procedure.

To start, an anesthesiologist will administer general anesthesia so that you’re asleep for the surgery. While you sleep, the provider performing your procedure will make the incision and use the laparoscope to take pictures of the pelvic region and look for lesions.

Oftentimes, your provider will likely make another incision close to the pubic hairline. This can help your provider remove any lesions or take tissue samples from your vaginal area for a biopsy, which is a lab test that can look for the presence of a health condition. Once the entire surgery is complete and the biopsy is done, your provider will stitch up your incision.

If needed, your provider may send a tissue sample to a lab for a biopsy to test the sample under a microscope. The sample can help your provider or lab technician look for signs of abnormal tissue growth, lesions, or cysts.

Blood Tests

In some cases, your healthcare provider may use a blood test to diagnose endometriosis. Research has found that people with endometriosis have higher levels of cancer antigen 125 (CA-125) in their blood than others.

For example, one study published in 2016 in the International Journal of Reproductive Biomedicine measured the CA-125 levels of 87 women with suspected endometriosis. The average CA-125 level was nearly 50 units per milliliter. In comparison, healthy CA-125 levels are typically between zero to 35 units per milliliter.

The researchers also found a link between CA-125 levels and factors like what stage of endometriosis someone is in and the size of their lesions. In particular, women with moderate-to-severe endometriosis were more likely to have higher CA-125 levels than those with mild endometriosis.

Genetic Testing

In order to receive a confirmation of endometriosis, your provider often has to use invasive diagnostic measures, like a laparoscopy. As research for endometriosis continues, experts have tried to develop less intrusive means for quickly diagnosing the condition.

For example, one study published in 2014 in Endocrinology demonstrated that genetic testing may help diagnose endometriosis. The researchers were able to develop a tool that looks for specific gene expressions (the appearance of an observable physical characteristic in your body) using genetic data and computer-based technology.

To develop the tool, the researchers took tissue samples from 77 women with endometriosis, 37 with other uterine or pelvic conditions, and 34 without any complications. Among the women with endometriosis, the researchers found that their genes triggered inflammation and an autoimmune response, unlike the women who did not have endometriosis.

According to the researchers, using their tool, healthcare providers could insert a catheter through the vagina and into the uterus to obtain a tissue sample. Experts believe this procedure may be quicker and less invasive than laparoscopy. In the study, the tool was 90% to 100% effective at diagnosing endometriosis. However, research remains ongoing on how to use genetic tests as a way to get reliable test results for endometriosis.

Barriers to Care

On average, people with endometriosis have symptoms for seven to nine years before receiving an accurate diagnosis of endometriosis. Those diagnostic delays happen because many people encounter barriers to adequate care and diagnosis for their condition. 

Generally, those barriers include the following:

• Normalization of period pain: People may learn to expect pain during their periods. In fact, the normalization of menstrual cramps is so widespread that some healthcare providers may undermine the severity of endometriosis-related pain. Some evidence also suggests that people who have periods can sometimes dismiss their own symptoms, making them less likely to seek out support for their pain.
• Lack of awareness: A lack of menstrual education during adolescence may cause people to not know about endometriosis. Without knowledge of endometriosis, people may not be inclined to seek treatment. Some evidence suggests a need for more knowledge about endometriosis among healthcare providers, too.
• Invasive diagnostic tests: Laparoscopy is a minimally invasive, but often costly, procedure. However, surgery is the only way to accurately diagnose endometriosis, which can pose financial challenges to those who may not have health insurance that covers the cost of the procedure.
• Limited treatments: Unfortunately, there is no cure for endometriosis as this time. Treatments don't always help improve symptoms and your symptoms often persist even after undergoing a laparoscopy to remove lesions or painful cysts.
• Inequities in healthcare: Research has found that myths about endometriosis being nearly nonexistent among people of color contribute to racial bias in gynecological healthcare. Those myths may lead to some racial groups having longer delays in receiving a proper diagnosis than white people. In other cases, some healthcare providers can also overlook endometriosis-related pain among non-cisgender women, which can worsen health outcomes for trans people.
  

Diagnostic Criteria

Another reason why people with endometriosis experience delays in their diagnosis is because there is a lack of agreed-upon diagnostic criteria. This is why you may have to jump through various hoops and undergo several rounds of testing with different healthcare providers before receiving an accurate diagnosis.

Generally, most healthcare providers will use your medical history, results from your pelvic exam, and pictures from imaging scans before recommending a laparoscopy to confirm an endometriosis diagnosis. However, this surgery comes with risks, so your healthcare provider will assess your symptoms and will need to suspect that you have signs of endometriosis before recommending a laparoscopy.

They will typically look for symptoms such as:

• Pain, which may happen during periods, sex, bowel movements, or urination 
• Infertility or trouble conceiving
• Abnormal menstrual bleeding, including heavy periods that last longer than eight days
• Short menstrual cycles
• Spotting between periods
• Gastrointestinal (GI) symptoms, like nausea, vomiting, and bloating

Your healthcare provider will also consider how your symptoms affect your day-to-day life. For example, painful periods that keep you from going to school or work may signal endometriosis. Additionally, if you are unable to become pregnant after one year of trying to conceive (if under the age of 35) or after six months of trying to conceive (if over 35 years old), endometriosis may be causing your infertility.

Stages of Endometriosis

If you do receive a diagnosis for endometriosis, your healthcare provider may also stage your condition. Developed by the American Society of Reproductive Medicine (ASRM), the following staging system describes the extent of lesions:

• Stage I: This is also known as minimal endometriosis. With stage I, there are small lesions and swelling in the pelvic region.
• Stage II: Also called mild endometriosis, stage II means that lesions are slightly more extensive than stage I. There may be minor organ damage and slight scarring or adhesions, which are bands between the organs.
• Stage III: This stage is referred to as moderate endometriosis. With stage III, lesions are prevalent and scarring and adhesions may be present.
• Stage IV: The last stage of endometriosis is severe endometriosis. Stage IV means that lesions have started to impact many organs and may distort the structure of the reproductive organs.

The number and size of lesions often do not affect symptoms and their severity. In other words, someone with minimal endometriosis may have more painful periods than someone with moderate endometriosis. However, the ASRM’s staging system does not take symptoms and their severity into account.

Screening for Related Conditions

Endometriosis symptoms, namely pain and infertility, resemble the symptoms of many other conditions. Therefore, ruling out other possible diagnoses is essential during your testing process.

For example, conditions affecting the reproductive organs with similar symptoms include:

• Pelvic inflammatory diseases (PID): PID can occur when bacteria spread from the vagina to other parts of your reproductive system during sexual activity. Like endometriosis, PID causes pain, especially during periods or while urinating. PID often involves sexually transmitted bacteria, such as chlamydia or gonorrhea.
• Primary dysmenorrhea: Primary dysmenorrhea occurs when you have painful periods that aren’t due to underlying conditions. You might experience symptoms like uncomfortable cramps and heavy bleeding.
• Adenomyosis: This condition happens when the endometrium grows into the uterine walls. Like endometriosis, adenomyosis can cause painful cramps and fatigue.
• Ovarian cysts: These are tiny, fluid-filled sacs that form inside the ovaries. Most of the time, ovarian cysts don’t cause symptoms. But if symptoms do occur, they may resemble endometriosis. For example, people with ovarian cysts may have spotting between periods or pain during sex.

Sometimes, conditions that affect your digestive and urinary systems can resemble endometriosis. Some of those conditions include the following:

• Irritable bowel syndrome (IBS): If you have IBS, you might experience uncomfortable symptoms such as abdominal pain, diarrhea, and constipation.
• Inflammatory bowel disease (IBD): This condition causes inflammation in your GI tract—or the passageway that runs from your mouth to your anus and through your digestive system. Oftentimes, IBD causes abdominal pain, diarrhea, weight loss, and fatigue. There are two types of IBD: Crohn’s disease and ulcerative colitis.
• Interstitial cystitis: Like endometriosis, this painful bladder condition may cause pain while urinating or during sex.