What Are the Different Types & Stages of Endometriosis?

“Your type of endometriosis plays a role in your symptoms & the treatment you will need”

In a nutshell, endometriosis is a condition whereby the tissue lining the inside of your uterus, (AKA endometrium), mistakenly grows outside of it. These growths, which are normally found in the abdomen or pelvis, and can grow on organs and linings such as the ovaries or fallopian tubes, are sometimes referred to as endometrial implants [1].

“Every month during the menstrual cycle, the mucous membrane tissue in the endometrial implants outside the womb, is also built up & shed. But because the blood & shed tissue can’t leave the woman’s body through her vagina, they stay near the endometrial implant” [2]

Thus, the shed tissue becomes trapped, leading to cysts, scarring, and inflammation. It is important to know that endometriosis is classed according to its type and stage. This grouping is based on various factors such as the quantity of tissue, its size, depth, and location [1].

So How is Endometriosis Measured?

“To classify which stage of endometriosis you have, your endometriosis specialist will evaluate you using a staging system which considers the extent, areas, & depth of endometrial lesions, together with the severity and presence of adhesions, & the presence & size of ovarian endometriomas”

There are a number of ways that this condition can be measured. One popular system involves designating points according to: the regions of the body that have been impacted; the depth of the endometrial tissue, and how much it has spread. According to the results, the endometriosis is graded by its stage:

• Stage 1 (minimal): In this case, there are only several wounds or lesions (abnormal changes or damage to the tissue) on the organs, or tissue lining the abdomen or pelvis. The quantity of scar tissue to small to none.
• Stage 2 (mild): At this level, more implants are present. Moreover, they are deeper within the tissue, and some scar tissue may be visible.
• Stage 3 (moderate): This stage indicates a substantial number of deep implants. Furthermore, one or both ovaries could have small cysts, and flimsy adhesions (heavy bands of scar tissue), are likely to be present.
• Stage 4 (severe): This phase is the most widespread. The patient has large cysts on one or both ovaries, as well as a substantial number of thick adhesions and deep implants [1].

•So Why Do Some Patients Suffer More Severe Endometriosis?

• At the present time, there is no conclusive research to indicate why this happens. Of note: this condition does not necessarily transition from one stage to the next. Moreover, if the endometriosis is not professionally treated, then over a period of time, it could ameliorate, get worse, or just remain the same [1]. However, whatever the case, regular professional examinations by a doctor specialising in endometriosis is essential.
• Putting a Spotlight on the Different Types of Endometriosis

This condition is also categorised according to the region of the abdomen or pelvis that the endometriosis is impacting. There are four general types:

• Number 1: Superficial Peritoneal Endometriosis. This type is the least severe. In this instance, the endometrial tissue adjoins to the thin membrane which lines the pelvis peritoneum and the abdomen. Of note, this also covers the majority of organs within these cavities.
• Number 2: Endometriomas. These type are known as chocolate cysts, because they are filled with dark fluid. They are most commonly discovered in the ovaries, although they may also be present in various parts of the abdomen or pelvis. They come in various sizes.
• Number 3: DIE (deeply infiltrating endometriosis). With this type, the endometrial tissue encroaches on the organs (for example: the bowels, bladder, rectum, and ovaries), either outside or within the pelvic cavity. Whilst it is not very common, in some instances a substantial amount of scar tissue can bind organs together, thus making them stuck. This scenario is referred to as frozen pelvis.
• Number 4: Abdominal wall endometriosis. With this type, the endometrial tissue can grow on the wall of the abdomen. Moreover, the cells can bond to an incision from a patient’s surgery (for example, their C-section) [1].

Does the Type & Stage of My Endometriosis Affect Treatment?
• Generally speaking, after studying your medical history, and conducting a comprehensive examination, your endometriosis specialist will plan your treatment according to
• your symptoms, and whether you are planning to have a baby. Specific pharmaceuticals to start relieving any pain you are experiencing, will be prescribed for you. Moreover, you may also be given hormonal therapy such as: gonadotropin-releasing agonists and antagonists; aromatase inhibitors, progestin therapy, and birth control pills [1].
• How Will My Type & Stage of Endometriosis Be Diagnosed?

“Endometriosis can be diagnosed via a medical examination, MRI imaging, or analysis of biomarkers (urine & blood tests). Keyhole surgery (laparoscopy) is however, the gold standard. “

In the first instance, during your consultation, your endometriosis specialist will conduct a pelvic exam in order to see if he/she can feel any cysts. In addition to this, the doctor may want you to take blood and urine tests, as well as an MRI (magnetic resonance imaging) in which a magnetic field and radio waves are used to generate detailed images of the tissues and organs in your body; or ultrasound (high-frequency sound waves which generate images of the inside of your body) [1].

Depending on your individual case, after you have had various standard tests, in some instances, you may be referred to a specialist surgeon who can carry out a laparoscopy (a common keyhole procedure which exposes what is going on inside your abdomen, and exposes superficial peritoneal endometriosis). This involves having a general aesthetic, as the physician has to make a very small incision close to your belly button, so that he/she can insert a laparoscope (a thin viewing instrument), into your abdomen, to enable him/her to spot any signs of endometrial tissue outside the womb. Further, in order to rule out certain causes of your symptoms, the surgeon may take a biopsy (a small tissue sample), which is then sent to the lab for testing [1].


[1]. Mayo Clinic (2020).

[2]. National Center for Biotechnology Information (NCBI) (2017). “What causes endometriosis?”