Endometriosis is a condition that attacks a woman’s reproductive system. It is characterised by the tissue that usually lines the uterus growing outside the uterus.
Tissue grown outside the uterus are known as endometriosis patches, implants, nodules or lesions. They are most commonly grown on or under the ovaries, on the uterus, bowels, bladder, and in rare circumstances, the lungs or other parts of the body.
In 1997, the American Society for Reproductive Medicine created a staging classification for Endometriosis. The staging classification allows surgeons to record the location, extent and depth of the endometriosis patches, severity and presence, and ovarian endometriomas (the endometrial tissue grown on the ovary).
The severity of Endometriosis is divided into four stages include minimal, mild, moderate and severe.
Stage 1 – Minimal
Endometriosis exists when there are implants, which can be mistaken for cysts or ovarian cancer. These implants cause irritation and inflammation to surrounding tissues leading to adhesions, where internal scar tissue bind to organs which can cause pain and dysfunction.
Stage 2 – Mild
Stage 1 is present, however, more aggressively. Adhesions have grown more intensely which causes irritation during ovulation, and pelvic pain. Adhesions also occur between the uterus and the rectum (this is called the Pouch of Douglas). Light lesions and shallow implants can appear on the ovary and pelvic lining.
Stage 3 – Moderate
Stage 1 and 2 are present, and adhesions involving the ovaries. Endometriomas (sometimes called chocolate cysts) begin to appear in this stage. Chocolate cysts get their name due to the blood inside the cyst turning dark red and brown. If the cysts rupture, they can cause extreme abdominal pain and inflammation in the pelvic area. Inflammation and infection can cause more adhesions.
Stage 4 – Severe
The final stage of Endometriosis is associated with a large number of cysts and severe adhesions. Neighbouring organs are usually involved (including the bladder, bowel and fallopian tubes), and the pelvis can be grossly distorted. Many cysts are found on the walls of the uterus and the rectum so women experiencing Stage 4 Endometriosis may experience digestive issues including painful bowel movements, constipation, nausea, vomiting and abdominal pain.
It is important to understand that staging assesses the physical disease only, and not the levels of pain or infertility. Staging does not necessarily correlate with the severity of the symptoms either. Some women who are classified as mild or Stage 1 may experience debilitating symptoms and pain, whereas other women classified as severe or Stage 4 may suffer little effect.