Endometriosis is a condition in which tissue similar to that lining the uterus grows in other parts of the body. Doctors tend to classify endometriosis according to its stage and type.
The classification for endometriosis stages that doctors most commonly use is the American Society for Reproductive Medicine (ASRM) system. The ASRM system ranks endometriosis using stages 1–4, which range in extent from minimal to severe.
The ASRM system gives an idea of the condition’s severity but not of the symptoms of pain and infertility. With this in mind, researchers
Doctors will also determine which of the three types of endometriosis a person has, as this will guide their treatment decisions.
In this article, we discuss the stages and types of endometriosis. We also look at how doctors diagnose and treat each stage and type of the condition.
Healthcare professionals group endometriosis into four stages according to the location of the endometrial-like tissue, as well as the amount, depth, and size.
According to a 2020 study, several staging systems are available to classify endometriosis. However, doctors do not consider any of them to be the gold standard.
The staging systems include:
- ASRM: This classification system has global acceptance and is the most well-known system. It is easy to use and helps doctors explain the extensiveness of the condition in simple terms.
- ENZIAN: This classification has poor international acceptance, and its complexity makes it difficult for people with the condition to understand. Doctors may use the ENZIAN classification to classify deep, infiltrating endometriosis because the system focuses on structures behind the peritoneum, which is the tissue that lines the abdominal wall.
- Endometriosis fertility index: This system predicts fertility outcomes in people who undergo endometrial surgery. Its disadvantages involve subjectivity in scoring and a lack of correlation with pain.
- American Association of Gynecological Laparoscopists classification: Experts are currently developing this system, which offers the advantages of acknowledging pain and infertility. It has not received validation yet.
The stages of endometriosis according to the ASRM staging system are as follows:
- Stage 1, or minimal: This stage covers scores of 1–5.
- Stage 2, or mild: This stage includes scores of 6–15.
- Stage 3, or moderate: Scores of 16–40 fall under this stage.
- Stage 4, or severe: Scores greater than 40 indicate stage 4.
Doctors score endometriosis depending on several factors, such as:
- the location, depth, and extent of endometrial-like growths
- the size of ovarian endometriomas, which are cystic masses comprising endometrial-like tissue
- the presence and severity of adhesions, which are fibrous bands that form between female reproductive organs
A doctor assigns each endometrial-like growth, endometrioma, or adhesion a score based on its size and severity. The more significant the size and severity, the higher the score.
Doctors use the ASRM system widely, but it has some disadvantages, including the fact that the stage does not correlate with pain or infertility. For instance, a person with stage 2 endometriosis
- superficial ovarian and peritoneal growths
- deep infiltrating endometriosis, which involves nodules comprising endometrial-like, fibromuscular, and adipose tissues
Doctors may suspect endometriosis after carrying out a pelvic exam or imaging tests, such as ultrasounds or MRIs. In such cases, they
Laparoscopy involves making a small incision in the abdomen and inserting a tube with a camera to view the pelvis. Doctors can see the locations of endometrial growths using laparoscopy. They can also record and describe the growths and then assign them a score. Adding the scores that they give to all the growths allows them to make a classification.
As symptoms do not necessarily link with stages, classifications cannot determine the best treatment options. Severe symptoms need medical intervention regardless of the stage.
There is currently no classification system with the specific aim of guiding treatment, so doctors may base their treatment decisions on symptoms rather than a classification.
Researchers have not extensively explored the extent to which endometriosis progresses. However, a few studies suggest that the condition does progress.
According to an older study from 2013, endometriosis is likely to progress if it appears during adolescence. The authors state that early diagnosis and treatment can prevent the development of severe lesions that may affect fertility.
An even earlier
Several classification systems exist for endometriosis stages, but the ASRM system is the one that doctors usually use. Doctors determine the stage of the condition with a laparoscopy, which enables them to see the endometrial-like growths inside the pelvis.
As none of the current classification systems correlate with pain, researchers do not recommend them as a basis for treatment. Instead, they encourage basing treatment on symptoms.