Polycystic Ovary Syndrome (PCOS): Rotterdam Criteria

The Rotterdam Consensus Criteria

The internationally standardized diagnosis of PCOS rigorously requires the clinical presence of at least two out of the three distinct, defining features established in Rotterdam (2003).

• 1. Oligo-ovulation or Anovulation: This typically manifests clearly as significant menstrual irregularity. Patients frequently report oligo-menorrhea (cycles consistently longer than 35 days apart) or complete secondary amenorrhea (an absolute absence of menses for six consecutive months).
• 2. Hyperandrogenism: This can be established identically by clinical or biochemical markers. Clinical hyperandrogenism unequivocally presents as marked hirsutism (excessive, coarse male-pattern terminal hair growth heavily involving the face, chest, and abdomen), severe resistant cystic acne, or male-pattern androgenic alopecia. Biochemical hyperandrogenism involves explicitly elevated fasting serum free testosterone or androstenedione levels.
• 3. Polycystic Ovarian Morphology (PCOM): Crucially, the isolated presence of 'polycystic ovaries' on a routine ultrasound alone absolutely does not confirm PCOS without the other clinical signs. Modern high-resolution transvaginal sonography criteria mandate the clear visualization of twenty or more small antral follicles (each measuring exactly 2 to 9 millimeters in diameter) tightly arranged within a single ovary, OR an absolutely increased total ovarian stroma volume explicitly exceeding 10 cubic centimeters (mL).

Classic Sonographic Hallmarks

High-frequency transvaginal ultrasound fundamentally defines the morphological extent of the disease.

• The String of Pearls Sign: Because the excess ovarian androgens halt the final maturation of normal follicles, these arrested sub-centimeter cysts characteristically align themselves immediately under the tough external ovarian capsule, creating a highly distinctive peripheral ring vividly resembling a rigid necklace or a perfect 'string of pearls.'
• Stroma Hypertrophy: The dense central ovarian stroma itself becomes distinctly highly echogenic (bright) and significantly bulky, forcing the arrested follicles to the extreme outer border.