Understanding Endometriosis Stages

Endometriosis happens when tissue similar to the lining of the uterus grows outside of it, forming lesions on the reproductive organs or nearby structures. To guide treatment, healthcare providers classify endometriosis into four stages using the American Society of Reproductive Medicine (ASRM) system.

These stages are based on lesion location, size, and depth, as well as the presence of ovarian cysts and adhesions. Importantly, the stage does not always reflect the level of pain a person feels—someone with mild disease may experience severe symptoms, while others with advanced disease may have minimal pain.

How Staging Works

The ASRM staging system uses a point-based method. Doctors assign points for:

  • Implants: their number, depth, and location

  • Adhesions: fibrous scar tissue that binds organs together

  • Ovarian cysts (endometriomas): size and severity

The total score determines the stage from I to IV, with higher scores representing more extensive disease.

Stage I: Minimal Endometriosis

Stage I is the earliest form, involving only a few superficial implants and mild adhesions.

  • Point range: 1–5

  • Common findings: Small lesions on pelvic structures, no major organ involvement

  • Symptoms: May include period pain, though some people remain symptom-free

Stage II: Mild Endometriosis

At this stage, implants may spread more widely and can grow deeper into tissue. Adhesions are still light, but the condition becomes more noticeable.

  • Point range: 6–15

  • Findings: Superficial or deeper lesions, mild adhesions

  • Impact: May start to affect fertility or cause stronger menstrual pain

Stage III: Moderate Endometriosis

Stage III is characterized by more extensive disease, including deeper implants and denser adhesions. Ovarian cysts may also be present.

  • Point range: 16–40

  • Findings: Deep lesions, thick adhesions, possible involvement of the cul-de-sac (space behind the uterus)

  • Impact: Fertility issues often become more common; surgery may be recommended in some cases

Stage IV: Severe Endometriosis

This is the most advanced stage, involving widespread lesions, severe adhesions, and often large ovarian cysts.

  • Point range: 40+

  • Findings: Extensive organ involvement, including intestines or rectum in some cases

  • Impact: May cause significant pelvic pain, infertility, and complications with organ function

Diagnosis

The only way to confirm endometriosis and determine the stage is through laparoscopy, a minimally invasive surgery that uses a camera to view lesions directly. Doctors may also take tissue samples for biopsy.

Imaging techniques like ultrasound or MRI can suggest endometriosis but cannot provide a definitive stage. Delays in diagnosis are common, with many patients waiting years before confirmation.

Treatment Options

Treatment does not depend solely on the stage but also on symptoms, fertility goals, and overall health. Options include:

  • Hormonal birth control to regulate or suppress periods

  • GnRH agonists or antagonists to lower estrogen levels

  • Pain relief with NSAIDs like ibuprofen

  • Surgery (laparoscopy) to remove lesions and scar tissue

  • Fertility treatments such as in vitro fertilization (IVF) if conception is a priority

Living With Endometriosis

Endometriosis is not life-threatening, but it can significantly affect quality of life. While there is no cure, treatment helps manage symptoms and improve daily functioning.

Self-care strategies that may help include:

  • Eating a balanced diet rich in fiber and anti-inflammatory foods

  • Staying physically active to improve circulation and reduce pain

  • Using heat therapy, such as a warm compress, for cramps

  • Practicing relaxation techniques like yoga or meditation

  • Following prescribed treatments consistently and consulting doctors about surgical options when needed