Stages of Endometriosis

The American Society of Reproductive Medicine classifies four stages based on the location, amount, depth, and size of the endometrial implants. Stage I is minimal, Stage II is mild, Stage III is moderate and Stage IV is severe. Criteria include:


--Extent of the spread of the implants

--Involvement of pelvic structures in the disease

--Extent of pelvic adhesions

--Blockage of the fallopian tubes

The stage of the endometriosis does not necessarily indicate the risk of infertility, the presence of other symptoms or how much pain a patient will experience.

For example, it is possible for a woman in Stage I to be in tremendous pain, while a woman in Stage IV may have no symptoms.In addition, women with impaired fertility who receive treatment during the first two stages of the disease have the greatest chance of regaining their ability to become pregnant following treatment.


Areas affected by endometriosis

  • Ovaries
  • The fallopian tubes
  • Ligaments that support the uterus
  • The internal area between the vagina and rectum
  • Outer surface of the uterus
  • In the lining of the pelvic cavity

Occasionally, implants are found in other places, such as:

  • Intestines
  • Rectum
  • Bladder
  • Vagina
  • Cervix
  • Vulva
  • Abdominal surgery scars