What is endometriosis and how is it diagnosed?
Last updated September 3, 2026.
Endometriosis is tissue like the uterine lining growing outside the uterus, where it inflames with each cycle - and pain is its signature. Diagnosis starts with a pelvic exam and history; ultrasound or MRI can spot larger deposits, but laparoscopy - a minor surgical look inside - is the definitive test, because small implants hide from scans. It is usually diagnosed between ages 25 and 40.
What to do
- Track the pain pattern. Period pain that worsens over time, pelvic pain between periods, or pain with sex are the patterns to report.
- Start with your OB-GYN. A pelvic exam and history come first; imaging follows.
- Know the limits of scans. A normal ultrasound does not rule endometriosis out - laparoscopy is the definitive test.
- Push if dismissed. Diagnosis delays of years are common; life-disrupting period pain is not something to simply endure.
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