How is Endometriosis Diagnosed?

Reviewed by: HU Medical Review Board | Last reviewed: June 2018

Diagnosing endometriosis can be challenging, as endometriosis can present in many ways and at various points throughout a woman's life. Additionally, some women may have the condition but experience few to no symptoms, while others may experience debilitating issues related to their endometriosis. Further, endometriosis shares similar symptoms with many other conditions ranging from urinary tract infections to inflammatory bowel disease, and many more in between, which can prolong the diagnostic process as potential conditions are narrowed down. Overall, receiving a diagnosis of endometriosis can take quite some time, with many receiving a diagnosis five to ten years after the onset of symptoms.1 Each individual's experience with the diagnostic process and its length can vary greatly, however, several common practices encountered are outlined below.

Medical and symptom history

If you are concerned that you may have endometriosis, or are experiencing possible endometriosis-related symptoms, the first step in the diagnostic process is to visit a healthcare provider. One of the first things they will do is take your medical and symptom history. This is a critical step in allowing your provider to understand what's going on with your body. A medical history contains information on an individual's past health-related events, such as any previous medical conditions, procedures, or history of any conditions running in their family. A symptom history focuses on the issues an individual is struggling with in the present, or recent past, that may shed light on any underlying, larger issues.

Providing the most accurate information possible is the best way to help your provider collect a full medical and symptom history. Questions you may be asked may vary based on the provider you see, and what they suspect is going on, however, being prepared to answer questions on your symptoms, knowing what medications you're taking, and bringing applicable medical records to your appointment are all ways to help provide the strongest medical and symptom history possible.

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Differential diagnosis

As you're giving this history to your provider, they will begin to speculate on what might be going on. Some conditions, like endometriosis, share symptoms with a variety of others, which can complicate the diagnostic process. When an individual describes having symptoms that could be related to several different conditions, a differential diagnosis is used. When your provider is performing a differential diagnosis, they are forming a list of all of the potential conditions that your symptoms may be related to, and then weighing the possibility of each condition against one another in order to determine what further tests and exams might be the most beneficial. The differential diagnostic process may take some time, and may be constantly evolving as an individual is describing their medical and symptom history. Several avenues may need to be pursued before a definitive answer is found.

Pelvic exam

A pelvic exam generally lasts a few minutes in length, and is a comprehensive evaluation of your reproductive system. When your provider performs a pelvic exam, they are checking your vagina, cervix, uterus, ovaries, pelvis, rectum, and vulva (the external portion of your vagina) for any issues. In order to examine these, your provider will look at the outside and the inside of your vagina, feel some of these structures internally, and may also take a small, internal sample of your cells called a Pap test. Typically, pelvic exams are recommended annually once a woman turns 21, however, their frequency or the timing of a woman's first exam may vary based on when she becomes sexually active or if she has a history of a previous gynecologic issue.2,3 Your provider will be able to determine how frequently you need to receive a pelvic exam, however, you can schedule your own anytime you are experiencing gynecologic symptoms that need addressed.

Imaging: Ultrasound, MRI, CT

After taking your medical and symptom history, and after performing a pelvic exam, your provider may recommend imaging. Imaging exams, such as ultrasound, MRI, or CT scans are used to take pictures of the inside of your body. They're used for a wide variety of purposes, including assessing injuries, monitoring the growth of a developing baby, looking for internal growths or tumors, and much more. Although the effectiveness of imaging exams in detecting potential signs of endometriosis is not as strong as laparoscopy, it is possible that some images may uncover endometriosis-related issues such as deep infiltrating endometriotic nodules or endometriomas (endometriosis-related ovarian cysts). This could help determine the extent of an individual's endometriosis. However, other conditions can cause ovarian cysts or other deeply infiltrating masses within the pelvis, so a laparoscopy may still be needed to definitively diagnose endometriosis despite seeing these findings on an image.4-6

Laparoscopy with biopsy

An individual will receive a definitive diagnosis of endometriosis following a laparoscopy.7,8 A laparoscopy is a minimally invasive surgical procedure that involves inserting a small, thin, camera-containing device into the abdomen to view the structures inside. This device is called a laparoscope, and it sends real-time footage back to the surgeon performing the procedure so that they can identify and assess any issues.7,9,10 In relation to endometriosis, your surgeon will look for any endometriosis lesions within your pelvis. If they see anything abnormal, including potential endometriosis patches, they will take a small sample of this tissue and send it to a pathologist for further investigation. This is called a biopsy. A pathologist is someone who is trained in looking at tissues underneath a microscope in order to diagnose different conditions.

A diagnostic laparoscopy is typically an outpatient procedure, meaning the individual undergoing the procedure will go home the same day. After the procedure, you may feel sleepy or uncomfortable from any remaining gas inside your abdomen, as well as sore at your incision site. Many people are able to go back to their normal activities within a few days of the procedure.9,10

Classification systems

The current staging method of endometriosis is based on guidelines outlined by the American Society for Reproductive Medicine (ASRM).11 The stages range from I (one) to IV (four), with I being the most mild and IV being the most severe. Again, these stages do not necessarily correlate with the symptoms experienced, as a woman with stage IV may be asymptomatic (experience no symptoms), while a woman with stage I may experience debilitating symptoms. Endometriosis is staged based on the location, depth, and extent of endometriosis lesions, the size and presence of any endometriomas (endometriosis-related ovarian cysts), the severity of any adhesions present (bundles of scar tissue that can adhere pelvic structures to one another), and any endometriosis-related blockages within the fallopian tubes. Each factor is scored, with higher scores indicating more advanced progression.

The ASRM staging guidelines were originally created to predict the fertility of a woman with endometriosis, however, a new system, the Endometriosis Fertility Index (EFI) has arisen for this purpose, and the ASRM system is used to classify condition progression as a whole. It has been theorized that the Endometriosis Fertility Index is a more reliable predictor of the possibility of becoming pregnant after surgical treatment of endometriosis when compared to the ASRM system. The EFI takes into account the functional status of the fallopian tubes, ovaries, and fimbriae (fingerlike projections that help facilitate egg movement from the ovaries to the fallopian tubes before potential fertilization). Additionally, the EFI takes into account a woman's age, amount of time she has been experiencing infertility, if she has been pregnant before, and her ASRM score. All of these together create one number on a scale of zero to ten. The closer to ten a woman scores, the higher the chances that she will become pregnant.12