What are the diagnostic criteria and treatment options for Polycystic Ovary Syndrome (PCOS)?

Diagnosis of Polycystic Ovary Syndrome (PCOS)

PCOS is diagnosed when at least two of three Rotterdam criteria are present: oligo/anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound, after excluding other disorders. 1, 2

Diagnostic Criteria

Clinical History Assessment

• Document menstrual cycle length: cycles >35 days indicate chronic anovulation, while cycles 32-35 days require further assessment for ovulatory dysfunction 1, 3
• Evaluate hyperandrogenism onset and duration: gradual development intensifying with weight gain suggests PCOS, whereas rapid onset with severe symptoms raises concern for androgen-secreting tumors 1, 3
• Assess for signs of androgen excess: acne (particularly severe or treatment-resistant), hirsutism, male-pattern balding (vertex, crown, or bitemporal), and clitoromegaly 1, 3
• Review medication use including exogenous androgens that could mimic PCOS 1
• Obtain family history of cardiovascular disease and diabetes 1

Physical Examination

• Calculate BMI and waist-hip ratio as metabolic markers 1
• Look for Cushing's syndrome features: buffalo hump, moon facies, hypertension, and abdominal striae to exclude this differential 1

Laboratory Evaluation

• Free testosterone is more sensitive than total testosterone for establishing androgen excess and should ideally be measured through equilibrium dialysis techniques 3
• Measure 17-hydroxyprogesterone to exclude non-classic congenital adrenal hyperplasia 1, 3
• Check thyroid function and prolactin levels to rule out thyroid disease and prolactin disorders 1

Ultrasound Assessment

Follicle number per ovary (FNPO) is the gold standard ultrasonographic marker for PCOS diagnosis in adult women. 4, 1

• Use FNPO ≥20 follicles as the diagnostic threshold: this provides sensitivity of 87.64% and specificity of 93.74% 4, 1
• Alternative threshold of ≥12 follicles can be used but has slightly lower diagnostic accuracy (sensitivity 82.98%, specificity 90.20%) 4
• Ovarian volume >10 mL serves as an alternative marker when FNPO cannot be accurately obtained 4, 1
• Use transvaginal ultrasound with ≥8 MHz transducer frequency for optimal resolution in adults 4, 1

Important caveat: The Rotterdam criteria from 2003 defined PCOM as ≥12 follicles per ovary, but newer ultrasound technology now allows detection of ≥25 follicles, and the ≥20 follicle threshold provides superior diagnostic accuracy 4, 3. This represents an evolution in diagnostic precision.

Special Population: Adolescents

• Do NOT use ultrasound as first-line investigation in adolescents <17 years old due to poor specificity, as large multicystic ovaries are common normal findings 1, 3
• Base diagnosis on oligomenorrhea persisting 2-3 years beyond menarche and biochemical evidence of hyperandrogenism 3
• Recognize that menstrual irregularities are physiologic in the first 2-3 years post-menarche due to hypothalamic-pituitary-ovarian axis immaturity 3

Differential Diagnosis to Exclude

The following conditions must be ruled out before confirming PCOS diagnosis:

• Cushing's syndrome: buffalo hump, moon facies, hypertension, abdominal striae 1
• Androgen-secreting tumors (ovarian or adrenal): rapid onset, severe hyperandrogenism, clitoromegaly 1
• Non-classic congenital adrenal hyperplasia: elevated 17-hydroxyprogesterone 1
• Thyroid disease and hyperprolactinemia 1
• Primary hypothalamic amenorrhea and primary ovarian failure 1

Metabolic Screening

All women with PCOS require systematic metabolic screening:

• Screen for type 2 diabetes and glucose intolerance in all patients 1
• Perform oral glucose tolerance testing (OGTT) if BMI >30 kg/m² even when fasting glucose is normal 1, 5
• Obtain fasting lipid profile to screen for dyslipidemia 1
• Measure blood pressure as part of cardiovascular risk assessment 1, 5

Emerging Diagnostic Tools

• Anti-Müllerian Hormone (AMH) shows promise as an alternative to ultrasound for detecting polycystic ovarian morphology, with significantly higher levels in PCOS patients 1, 3
• Current limitation: lack of standardized assays and established cut-offs prevents routine clinical use 1, 6

Geographic and Criteria Variations

The Rotterdam criteria are used more frequently in European (44%) and Asian (71%) studies, while North American studies predominantly use the 1990 NIH criteria (100%) 4. The Rotterdam criteria demonstrate higher pooled sensitivity, supporting their broader adoption 4.