What is the staging system for endometriosis?

During laparoscopy, the surgeon determines the number, size, and location of endometrial implants and adhesions and uses this information to stage endometriosis using the revised American Fertility Society (AFS) staging system depending on the extent of the disease:

• Minimal (stage I)
  
• Mild (stage II
  
• Moderate (stage III)
  
• Severe (stage IV)