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Published on: 7/14/2026

How is Polycystic Ovary Syndrome diagnosed using ultrasound?

Yoshinori Abe

Reviewed by Yoshinori Abe, MD

Internal Medicine

Polycystic Ovary Syndrome (PCOS) is diagnosed on ultrasound by evaluating key features of the ovaries, including follicle count, follicle size, and overall ovarian volume. According to the Rotterdam criteria, an ovary is considered polycystic if it contains 12 or more follicles measuring 2–9 mm in diameter, or if the ovarian volume exceeds 10 mL. Ultrasound is typically used alongside blood tests and a review of symptoms — such as irregular periods, acne, or excess hair growth — to confirm a PCOS diagnosis.

If you're experiencing symptoms that could point to PCOS, early insight matters. Hormonal imbalances left unaddressed can affect fertility, metabolism, and long-term health. Taking a free, instant, online symptom check can help you understand what your body may be signaling and guide you toward the right next steps — whether that's scheduling an ultrasound, seeing a specialist, or asking your doctor the right questions.

Reviewed for medical accuracy: 07/14/2026

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Important Next Steps

Learn if PCOS symptoms suggest another causeDiscover what your PCOS symptoms meanSee if your ultrasound points to PCOSFind OTC options for PCOS symptom reliefFind a doctor for PCOS careUnderstand home remedies for PCOS symptomsFind out if you likely have PCOS

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Explanation

Polycystic Ovary Syndrome (PCOS) is a condition that affects the ovaries. Doctors use ultrasound to help diagnose it. An ultrasound is like a special camera that lets doctors see inside the body.

Key Features on Ultrasound

  1. Follicles: In PCOS, the ovaries have many tiny sacs called follicles. On an ultrasound, doctors look for 12 or more of these follicles in each ovary.
  2. Ovary Size: The ovaries are often larger than usual in PCOS, so doctors check if the ovary volume is greater than 10 cubic centimeters.

These ultrasound features help doctors decide if someone might have PCOS, but they also consider other signs and symptoms, like irregular periods or hormone levels, to make a full diagnosis. If you're experiencing symptoms that concern you, try our free AI symptom checker to better understand what might be happening with your health and when to seek medical care.

(References)

  • Zhu RY, Wong YC, & Yong EL. (2016). Sonographic evaluation of polycystic ovaries. Best practice & research. Clinical obstetrics & gynaecology, 27118252.

  • Di Michele S, Fulghesu AM, Pittui E, Cordella M, Sicilia G, Mandurino G, et al. (2025). Ultrasound Assessment in Polycystic Ovary Syndrome .... Biomedicines, 40002866.

  • Dewailly D, Gronier H, Poncelet E, Robin G, Leroy M, Pigny P, et al. (2011). Diagnosis of polycystic ovary syndrome (PCOS). Human reproduction (Oxford, England), 21926054.

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