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Difficulty: MediumReproductive Endocrinology and Infertility

A 27-year-old female patient seeks medical evaluation because she has been unable to conceive for the past year and a half. She notes that her menses are infrequent, occurring only 5 to 6 times per year. She also reports progressive, unwanted hair growth on her face and abdomen over the last four years. She has no other medical conditions and does not take any prescription medications. Her body mass index is 30 kg/m2 and blood pressure is 118/76 mm Hg. On physical examination, terminal hairs are noted on her chin, upper lip, and lower abdomen. No clitoromegaly or purple striae are observed. Transvaginal ultrasonography reveals polycystic morphology in both ovaries. Serum levels of prolactin and thyroid-stimulating hormone are within normal reference ranges. Which of the following is the most appropriate test to perform next to establish the etiology of her symptoms?

  1. Measurement of serum 17-hydroxyprogesteroneAnswer
  2. B
    Measurement of fasting serum insulin
  3. C
    Calculation of the luteinizing hormone to follicle-stimulating hormone ratio
  4. D
    Overnight dexamethasone suppression test
  5. E
    Endometrial biopsy

Answer

Measurement of serum 17-hydroxyprogesterone
According to the Rotterdam criteria, the diagnosis of polycystic ovary syndrome (PCOS) requires at least two of the following three features: oligo-ovulation or anovulation, clinical or biochemical signs of hyperandrogenism, and polycystic ovaries on ultrasound. Crucially, other etiologies of hyperandrogenism and menstrual irregularity must be excluded to finalize the diagnosis. Non-classic congenital adrenal hyperplasia (NCCAH), typically caused by a partial 21-hydroxylase deficiency, can present with symptoms identical to PCOS (hirsutism, acne, irregular menses, and polycystic ovaries). Therefore, clinical guidelines mandate measuring a morning, early follicular phase serum 17-hydroxyprogesterone level in all women presenting with suspected PCOS to rule out NCCAH before making a definitive diagnosis.

Step-by-Step Solution

1
Identify the patient's primary clinical syndrome based on the presentation.
The patient presents with oligo-ovulation (infrequent menses), clinical hyperandrogenism (hirsutism), and polycystic ovaries on ultrasound.
These three findings fulfill the Rotterdam criteria for suspected polycystic ovary syndrome (PCOS), pending the exclusion of other mimicking etiologies.
2
Determine the necessary diagnostic workup to finalize the diagnosis.
Other disorders that mimic PCOS must be formally ruled out. Thyroid disease and hyperprolactinemia have already been excluded with normal laboratory results. The next most critical condition to exclude is non-classic congenital adrenal hyperplasia (NCCAH).
Because PCOS is a diagnosis of exclusion, and NCCAH can present identically to PCOS, it must be excluded by measuring a basal serum 17-hydroxyprogesterone level.

Key Concept

Polycystic ovary syndrome (PCOS) is a diagnosis of exclusion; patients presenting with hyperandrogenism and irregular menses must have a serum 17-hydroxyprogesterone level checked to rule out non-classic congenital adrenal hyperplasia.
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Topics

Reproductive Endocrinology and Infertility

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