How is PCOS diagnosed vs. endometriosis?

PCOS is typically diagnosed using the Rotterdam criteria: you meet the diagnosis when two of three are present—irregular or absent ovulation, signs of higher androgens (on exam or labs), and a polycystic-appearing ovary pattern on ultrasound—after ruling out other conditions that can mimic it. Pelvic pain is not part of the diagnostic criteria for PCOS, even though some people with PCOS can still experience discomfort for other reasons.

Endometriosis is different: it’s a condition where endometrial-like tissue grows outside the uterus and is much more closely tied to pelvic pain, painful periods, pain with sex, bowel or bladder symptoms, and fertility challenges. Imaging can sometimes suggest endometriosis or related disease patterns, but endometriosis can also be present even when imaging is normal; the most definitive way to confirm it is to directly visualize and surgically evaluate lesions. If your symptoms don’t fit neatly into a PCOS picture—or you suspect you may have both—our team can help sort out the workup and next steps in a consultation.