Staging is a way of describing how mild or severe a condition is. The stage of the endometriosis is determined by looking at the uterus, fallopian tubes, and ovaries and inside the abdomen and lower pelvic area. Usually, this is done with a viewing instrument inserted through a small abdominal incision (laparoscopy). However, endometriosis is sometimes first found during surgery for an unrelated condition.

Endometriosis is classified in four stages:

• Stage I: minimal
• Stage II: mild
• Stage III: moderate
• Stage IV: severe

The stage of the endometriosis is based on the:

• Location of endometriosis growths (implants).
• Number of places the implants are found.
• Depth the implants penetrate into normal tissue.
• Severity of the scar tissue (adhesions) around the implants.