Diagnosis of Polycystic Ovary Syndrome (PCOS)

Diagnostic Criteria

• The American College of Family Physicians recommends that the diagnosis of PCOS requires the presence of at least two of three criteria: hyperandrogenism (clinical or biochemical), ovulatory dysfunction (oligo or anovulation), and polycystic ovarian morphology on ultrasound, after excluding other causes of androgen excess 1
• The American College of Family Physicians suggests measuring total or free testosterone as first-line tests, preferably using mass spectrometry (LC-MS/MS) which shows superior specificity (92%) compared to direct immunoassays (78%) 2

Evaluation of Laboratory Tests

• The American College of Family Physicians recommends measuring TSH to exclude thyroid disease as a cause of menstrual irregularity 1
• The American College of Family Physicians suggests measuring prolactin levels to exclude hyperprolactinemia 1
• The American College of Family Physicians recommends a 2-hour oral glucose tolerance test (75g) to detect type 2 diabetes and glucose intolerance, regardless of BMI 1, 2, 3

Anthropometric Evaluation

• The American College of Family Physicians recommends calculating BMI and waist-to-hip ratio to evaluate central obesity 1, 3
• The American College of Family Physicians suggests looking for acanthosis nigricans on physical examination (neck, axillae, under breasts, vulva), which indicates underlying insulin resistance 1, 3

Exclusion of Other Causes of Hyperandrogenism

• The American College of Family Physicians recommends measuring 17-hydroxyprogesterone to exclude congenital adrenal hyperplasia 1
• The American College of Family Physicians suggests considering dexamethasone suppression test to exclude Cushing's syndrome 1, 2

Metabolic Evaluation

• The American College of Family Physicians recommends that all women with PCOS should be screened for metabolic dysfunction regardless of body weight, as insulin resistance occurs independently of BMI and affects both lean and overweight women 3
• The American College of Family Physicians suggests that women with PCOS have a higher risk of glucose intolerance, type 2 diabetes, hepatic steatosis, and metabolic syndrome, hypertension, dyslipidemia, vascular thrombosis, stroke, and possibly cardiovascular events 3

Diagnostic and Evaluation of Polycystic Ovary Syndrome (PCOS)

Ultrasound Evaluation

• The Endocrine Society recommends that ultrasound should not be used for diagnosis in patients with a gynecological age < 8 years due to the high incidence of multifollicular ovaries at this stage, and the threshold for polycystic ovarian morphology is: ≥20 follicles per ovary and/or an ovarian volume ≥10 ml, with no corpus luteum, cyst, or dominant follicle present 4
• The American College of Obstetricians and Gynecologists suggests that a transvaginal approach should be prioritized if the patient is sexually active and it is acceptable to her, with endovaginal transducers including a frequency of 8 MHz 4
• In patients with irregular cycles and hyperandrogenism, ultrasound is not necessary for diagnosis but will identify the complete PCOS phenotype, according to the European Society of Human Reproduction and Embryology 4
• The use of serum anti-Müllerian hormone (AMH) levels should not be used as an alternative for detecting polycystic ovarian morphology or as a single test for PCOS diagnosis, as recommended by the American Society for Reproductive Medicine 4

Diagnostic Criteria and Considerations for PCOS in Adolescents

Diagnostic Limitations and Criteria

• The American College of Endocrinology recommends that ultrasound should not be used for PCOS diagnosis in adolescents with gynecological age <8 years due to the high incidence of multifollicular ovaries being physiologically normal at this life stage 5
• The Endocrine Society suggests that ovarian morphology should not be used as diagnostic criteria for PCOS in adolescents <8 years post-menarche 5
• Transabdominal ultrasound is acceptable for non-sexually active adolescents, focusing on ovarian volume ≥10 mL, according to the American College of Radiology 5, 6

Imaging Considerations

• The American College of Radiology recommends that transvaginal ultrasound is preferred if sexually active and acceptable to the patient, using transducers with frequency bandwidth including 8 MHz 5
• MRI without IV contrast may be useful in obese adolescents where ultrasound is limited, providing reproducible ovarian volume assessment, as suggested by the American College of Radiology 6, 7
• The threshold for polycystic ovarian morphology is ≥20 follicles per ovary (2-9mm) and/or ovarian volume ≥10 mL, with no corpus luteum, cyst, or dominant follicle present, according to the Endocrine Society 5

Diagnostic Criteria and Evaluation for Polycystic Ovary Syndrome (PCOS)

Clinical Assessment

• The presence of clinical hyperandrogenism—hirsutism, acne, male‑pattern alopecia, or clitoromegaly—should be systematically evaluated in all women suspected of PCOS. 8
• Lifestyle factors (dietary habits, physical activity, alcohol consumption, and tobacco use) are important components of the initial PCOS work‑up. 8
• A detailed family history of cardiovascular disease and type 2 diabetes is recommended because these conditions are more prevalent in women with PCOS. 8
• Physical examination should include assessment for insulin‑resistance markers such as body‑mass index, waist‑to‑hip ratio, and acanthosis nigricans on the neck, axillae, or other sites. 8
• Pelvic examination to detect ovarian enlargement is part of the routine clinical evaluation. 8
• Screening for signs of Cushing syndrome (e.g., “buffalo hump,” moon facies, central obesity, easy bruising, proximal myopathy) is advised to exclude this differential diagnosis. 8

Laboratory Evaluation

• Serum thyroid‑stimulating hormone (TSH) measurement is required to rule out thyroid disease as a cause of menstrual irregularities. 8
• Morning fasting prolactin should be measured to exclude hyperprolactinemia; any elevated result must be confirmed with 2–3 repeat samples taken 20–60 minutes apart. 8
• If clinical features suggest Cushing syndrome, a dexamethasone‑suppression test should be performed. 8

Metabolic Assessment

• All women with PCOS, irrespective of body weight, must undergo a 2‑hour 75‑g oral glucose tolerance test to identify type 2 diabetes mellitus or impaired glucose tolerance. 8
• A fasting lipid panel—including total cholesterol, LDL‑C, HDL‑C, and triglycerides—is recommended to evaluate cardiovascular risk. 8
• Body‑mass index and waist‑to‑hip ratio should be recorded to assess central obesity and related metabolic risk. 8
• Chronic anovulation, obesity, hyperinsulinemia, and reduced sex‑hormone‑binding globulin (SHBG) confer an increased risk of endometrial carcinoma in PCOS patients. 8

Imaging Criteria (Ultrasound)

• The follicle number per ovary (FNPO) is the most accurate sonographic marker for PCOS, demonstrating a sensitivity of 87.6 % and specificity of 93.7 %. 9

Associated Risks

• Women with PCOS have a markedly increased risk of endometrial cancer due to the combination of chronic anovulation, obesity, hyperinsulinemia, and low SHBG levels. 8

Guideline Recommendations for Imaging in Suspected Polycystic Ovary Syndrome

Preferred Primary Imaging Modality

• Transvaginal ultrasound using a transducer with a frequency bandwidth of ≥ 8 MHz is the recommended first‑line imaging technique for evaluating polycystic ovarian morphology in reproductive‑age women with suspected PCOS, because it provides the highest resolution for follicle counting and ovarian volume measurement. 10

First‑Line Imaging Approach

• When the patient is sexually active and consents to the procedure, transvaginal ultrasound should be employed as the initial imaging study, as it offers superior visualization of ovarian follicles and more accurate ovarian volume assessment compared with other approaches. 10

Diagnostic Thresholds for Polycystic Ovarian Morphology

• On either ovary, the ultrasound must demonstrate ≥ 20 follicles measuring 2–9 mm in diameter and/or an ovarian volume of ≥ 10 mL; measurements must be performed in the absence of a corpus luteum, cysts, or dominant follicles ≥ 10 mm. 10

Alternative Imaging When Transvaginal Ultrasound Is Not Feasible

• Transabdominal ultrasound may be used for patients who are not sexually active or who decline transvaginal scanning; in this setting, reporting should focus on ovarian volume ≥ 10 mL because reliable follicle counting is limited. 10
• Magnetic resonance imaging (MRI) of the pelvis without contrast is an option when ultrasound cannot adequately visualize the ovaries, particularly in obese patients; MRI provides reproducible ovarian volume measurements and can depict follicle patterns, although it is not required for routine evaluation. 10

Situations in Which Ultrasound Should Not Be Used

• Ultrasound should be avoided for PCOS diagnosis in individuals whose gynecological age is < 8 years after menarche, because multifollicular ovaries are physiologically normal during this early post‑menarcheal period. 10

Situations in Which Ultrasound Is Not Required

• In patients who already meet both criteria of irregular menstrual cycles and clinical/biochemical hyperandrogenism, ovarian ultrasound is not mandatory for establishing a PCOS diagnosis according to the Rotterdam criteria, although it can help define the complete phenotype. 10

Essential Reporting Standards for Ovarian Ultrasound

• The ultrasound report must include:
  [All items cited] [10]

Biomarker Limitations

• Anti‑Müllerian hormone (AMH) levels should not be used as a substitute for imaging to detect polycystic ovarian morphology or as a standalone diagnostic test for PCOS, because assay standardization and validated cut‑offs are lacking. 10

Threshold Updates and Technological Considerations

• Although newer high‑frequency probes have suggested that a threshold of ≥ 26 follicles may improve discrimination between PCOS and normal ovaries, current international endocrine guidelines continue to endorse the ≥ 20‑follicle threshold for standardization and comparability across practices. 10