Endometriosis happens when tissue similar to the lining of the uterus—called the endometrium—starts to grow outside of the uterus. These growths, also called lesions, may appear around the pelvis, on the ovaries, fallopian tubes, or even spread to nearby organs like the bladder or colon.

Lesions can lead to pelvic pain, menstrual changes, infertility, and other disruptive symptoms. If you suspect endometriosis, visiting a healthcare provider is the first step toward diagnosis. The process usually includes a detailed medical history, a pelvic exam, imaging scans, and sometimes blood tests. But the only way to confirm endometriosis is through laparoscopy, a minimally invasive surgery that allows doctors to see and test the lesions directly.

Medical History

Your provider will begin by asking questions about your symptoms, cycle, and family history. Expect to answer questions such as:

  • When did your symptoms begin?

  • How severe are they, and do they interfere with daily activities?

  • Do they worsen during your period?

  • How long and heavy are your menstrual cycles?

  • Has anyone in your family been diagnosed with endometriosis?

  • Have you had trouble conceiving?

This information helps guide the next steps of testing.

Pelvic Exam

A pelvic exam allows the provider to check for tenderness, nodules, or structural changes. Using clean gloves and sometimes a speculum, the provider will carefully examine your pelvic area.

While this exam can highlight abnormalities, it is not a reliable way to diagnose endometriosis on its own. Abnormal findings usually lead to further testing.

Imaging Tests

Imaging gives a closer look at your pelvic organs:

  • Ultrasound: A transducer is placed inside the vagina or on the abdomen to create images. It can reveal thick tissue, nodules, or cysts.

  • MRI: Ordered when ultrasound results are inconclusive, MRI provides detailed pictures and is especially useful for deep infiltrating endometriosis (DIE).

These methods are helpful but may not detect small lesions.

Laparoscopy

Laparoscopy is the gold standard for confirming endometriosis. Under general anesthesia, a surgeon makes a small incision in the abdomen and inserts a laparoscope to view the pelvic region. Tissue samples may also be collected for biopsy.

This procedure not only diagnoses but can also remove lesions, helping with both confirmation and treatment.

Blood Tests

Some providers use blood tests to measure CA-125, a protein often elevated in people with endometriosis. Higher levels are linked to more advanced disease, but the test alone cannot confirm a diagnosis.

Genetic Testing

Researchers are exploring genetic testing as a less invasive option. Early studies show that analyzing gene expressions related to inflammation may help identify endometriosis. While promising, this method is still under research.

Barriers to Diagnosis

Most people wait 7–9 years for an accurate diagnosis due to:

  • Normalization of menstrual pain

  • Lack of awareness in both patients and providers

  • Costs and risks of laparoscopy

  • Racial and gender biases in healthcare

  • Limited treatment options even after diagnosis

These barriers often delay proper care and worsen symptoms over time.

Diagnostic Criteria

Healthcare providers typically use a combination of history, pelvic exam, and imaging before recommending laparoscopy. Symptoms that raise suspicion include:

  • Pain during periods, sex, urination, or bowel movements

  • Heavy or irregular menstrual bleeding

  • Infertility or difficulty conceiving

  • GI symptoms such as bloating or nausea

Stages of Endometriosis

The American Society of Reproductive Medicine classifies endometriosis into four stages:

  • Stage I (Minimal): Few, small lesions

  • Stage II (Mild): More extensive lesions with slight scarring

  • Stage III (Moderate): Clear lesions, adhesions, and organ involvement

  • Stage IV (Severe): Widespread lesions with significant organ distortion

Severity of pain does not always match the stage.

Screening for Related Conditions

Because endometriosis symptoms overlap with other conditions, providers often rule out:

  • Pelvic inflammatory disease (PID)

  • Primary dysmenorrhea (painful periods without underlying disease)

  • Adenomyosis

  • Ovarian cysts

  • GI disorders like IBS and IBD

  • Interstitial cystitis (painful bladder syndrome)

A Quick Review

Endometriosis is challenging to diagnose because symptoms mimic other conditions, and confirmation requires laparoscopy. Providers rely on history, exams, imaging, and sometimes blood or genetic tests to guide the process. Barriers like lack of awareness and healthcare inequities often delay diagnosis. Early evaluation and persistence in seeking care can help patients get the answers—and relief—they need.