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

Testing for PCOS

Diagnose PCOS when at least 2 of 3 criteria are present: hyperandrogenism (clinical or biochemical), ovulatory dysfunction (oligo/anovulation), and polycystic ovarian morphology on ultrasound—but only after excluding other causes of androgen excess. 1, 2

Diagnostic Criteria (Rotterdam Criteria)

The diagnosis requires at least 2 of the following 3 features 1, 2, 3, 4:

• Oligo- or anovulation: Document menstrual history with cycle length >35 days suggesting chronic anovulation 1
• Clinical and/or biochemical hyperandrogenism: Look for acne, balding, hirsutism, clitoromegaly on exam, or elevated androgen levels on testing 1
• Polycystic ovarian morphology (PCOM) on ultrasound: ≥20 follicles per ovary (2-9mm diameter) OR ovarian volume >10 mL 1, 2

Essential Clinical Evaluation

History and Physical Examination

• Evaluate onset and duration of signs of androgen excess 1
• Document menstrual history with specific attention to cycle length 1
• Review medication use, including exogenous androgens 1
• Assess lifestyle factors: diet, exercise, alcohol use, smoking 1
• Obtain family history of cardiovascular disease and diabetes 1
• Calculate BMI and waist-hip ratio to evaluate central obesity 1, 2
• Look for acanthosis nigricans (neck, axillae, under breasts, vulva) indicating insulin resistance 2

Laboratory Testing

First-Line Androgen Testing

Total testosterone via LC-MS/MS is the single best initial biochemical marker with 74% sensitivity and 86% specificity 1:

• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the preferred measurement method, offering superior specificity (92% vs 78%) compared to direct immunoassays 1, 2
• Calculated free testosterone using the Vermeulen equation has the highest sensitivity at 89% with 83% specificity 1
• Free androgen index (FAI) has 78% sensitivity and 85% specificity, but use cautiously when SHBG <30 nmol/L 1
• Androstenedione has 75% sensitivity and 71% specificity, useful when SHBG is low 1
• DHEAS has 75% sensitivity and 67% specificity, particularly valuable in women <30 years 1

Exclusion of Other Causes

You must rule out other hyperandrogenic disorders before confirming PCOS 1, 2:

• Measure TSH to exclude thyroid disease 2
• Measure prolactin to exclude hyperprolactinemia 2
• Measure 17-hydroxyprogesterone to exclude congenital adrenal hyperplasia 2
• Consider dexamethasone suppression test to exclude Cushing's syndrome (look for buffalo hump, moon facies, hypertension, abdominal striae) 1, 2
• Rule out androgen-secreting tumors (rapid onset and severe hyperandrogenism) 1

Ultrasound Assessment

Technical Specifications

Use transvaginal ultrasound with ≥8 MHz transducer frequency for optimal resolution in adults 1, 2:

• Follicle number per ovary (FNPO) ≥20 follicles is the gold standard, with 87.64% sensitivity and 93.74% specificity 1
• Ovarian volume >10 mL serves as an alternative threshold when accurate follicle counting is difficult 1, 2
• Follicle number per single cross-section (FNPS) is a secondary alternative marker 1
• No corpus luteum, cyst, or dominant follicle should be present 2

Critical Age-Specific Considerations

Do NOT use ultrasound as a first-line diagnostic tool in adolescents (<20 years, at least 1 year post-menarche) due to poor specificity and high false-positive rates 1, 2:

• In adolescents, rely on clinical and biochemical hyperandrogenism plus menstrual irregularity persisting 2-3 years beyond menarche 1
• Women should be >8 years post-menarche before using ultrasound for PCOS diagnosis 1, 2

Important Pitfall

Up to one-third of reproductive-aged women without PCOS have polycystic ovarian morphology on ultrasound, so the presence of multiple small follicles alone is insufficient for diagnosis 1. In patients with irregular cycles AND hyperandrogenism, ultrasound is not necessary for diagnosis but will identify the complete PCOS phenotype 2.

Metabolic Screening

All women with PCOS should be screened for metabolic dysfunction regardless of body weight, as insulin resistance occurs independently of BMI 2:

• Perform 2-hour oral glucose tolerance test (75g) to detect type 2 diabetes and glucose intolerance, regardless of BMI 2
• Screen for dyslipidemia with fasting lipoprotein profile 1
• Measure fasting glucose and triglycerides, HDL cholesterol 5
• Monitor blood pressure 5

Special Testing Considerations

Hormonal Contraception Interference

Remove or allow expiration of progestin-only implants (e.g., Implanon) before testing, as they suppress the hypothalamic-pituitary-ovarian axis and make hormone levels unreliable 1:

• LH/FSH ratio becomes unreliable due to progestin suppression 1
• Biochemical hyperandrogenism testing requires testing in the absence of hormonal contraception 1

AMH Testing

Do NOT use serum anti-Müllerian hormone (AMH) levels as an alternative for detecting PCOM or as a single test for PCOS diagnosis 1, 2:

• AMH is elevated in PCOS but lacks standardization across assays and established cut-offs 1
• AMH is being investigated but not yet recommended for clinical diagnosis 1

Common Pitfalls to Avoid

• Transient multifollicular appearance can occur after discontinuing birth control and does not necessarily represent true PCOS 1
• Excessive exercise patterns can cause hypothalamic suppression and amenorrhea, mimicking PCOS 1
• Do not diagnose hirsutism based solely on Ferriman-Gallwey score 5
• Screening for elevated plasma LH is no longer necessary, and GnRH testing serves no purpose 5