Hyperandrogenism + ovulatory dysfunction + polycystic ovarian morphology; insulin resistance is the common thread.
Also known as: PCOS, Stein-Leventhal syndrome, polycystic ovaries, functional ovarian hyperandrogenism, PMOS, polyendocrine metabolic ovarian syndrome
Overview
Heterogeneous endocrine disorder of reproductive-age women defined (Rotterdam 2003) by 2 of 3 criteria: oligo- or anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound — after exclusion of other causes. In 2026 an international consensus renamed the condition polyendocrine metabolic ovarian syndrome (PMOS); PCOS remains in wide use during the transition.
Epidemiology
Affects 8-13% of reproductive-age women worldwide; most common endocrinopathy in this group and a leading cause of anovulatory infertility.
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Question 1ReproductiveMedium
A 28-year-old woman with obesity has oligomenorrhea, hirsutism, and acne. Pelvic ultrasound shows bilateral ovaries each with >=20 follicles. Laboratory studies show an elevated LH (luteinizing hormone):FSH (follicle-stimulating hormone) ratio and a mildly elevated free testosterone. Which of the following is the most appropriate first-line management?
ASpironolactone therapy
BGlucocorticoid replacement
CLifestyle modification
DLaparoscopic ovarian drilling
EEstrogen replacement
Reveal answer & full explanation
Correct answer: C — Lifestyle modification
ASpironolactone therapy
BGlucocorticoid replacement
CLifestyle modification✓
DLaparoscopic ovarian drilling
EEstrogen replacement
Why lifestyle modification is correct
Oligomenorrhea, clinical and biochemical hyperandrogenism (hirsutism, acne, elevated free testosterone), and polycystic ovarian morphology satisfy the Rotterdam criteria (2 of 3) for polycystic ovary syndrome.
In a patient with obesity, lifestyle modification with 5-10% weight loss is first-line: it lowers androgens, improves insulin sensitivity, and restores ovulation in many patients.
Combined oral contraceptives, metformin, and letrozole are added for menstrual regulation, insulin resistance, and ovulation induction respectively, but behavioral change comes first.
Why the others are wrong
Estrogen replacement — these patients are estrogen-replete; unopposed estrogen would worsen endometrial risk and does not treat hyperandrogenism. Sets the confused-with-hypoestrogenism trap.
Glucocorticoid replacement — reserved for adrenal causes of hyperandrogenism such as non-classic congenital adrenal hyperplasia; the LH:FSH ratio and ovarian morphology point to an ovarian source. Sets the confused-with-CAH trap.
Laparoscopic ovarian drilling — a later-line option for ovulation induction in patients resistant to letrozole or clomiphene, and it addresses neither the metabolic driver nor the hirsutism. Sets the right-treatment-wrong-step trap.
Spironolactone therapy — the antiandrogen is tempting for hirsutism and acne, but it is a second-line agent, generally added when hirsutism persists after about 6 months of an estrogen-progestin contraceptive or used when one cannot be taken, and it requires reliable contraception because it can feminize a male fetus; it does not address the obesity and insulin resistance driving this presentation. Sets the treat-the-symptom trap.
Question 2ReproductiveMedium
A 25-year-old woman reports menstrual cycles every 45 to 60 days, increasing facial and chin hair, and difficulty losing weight; her BMI is 32. Examination shows coarse terminal hair on the upper lip and chin. Laboratory studies reveal elevated free testosterone, a normal 17-hydroxyprogesterone, normal TSH and prolactin, and a luteinizing hormone to follicle-stimulating hormone ratio of 3:1. Transvaginal ultrasound shows multiple small peripheral follicles in each ovary. After excluding other causes, which of the following combinations of findings establishes the diagnosis of polycystic ovary syndrome by the Rotterdam criteria?
AOligo-ovulation with an elevated LH to FSH ratio above 2
BHirsutism with an elevated serum free testosterone level
COligo-ovulation with clinical or biochemical hyperandrogenism
DPolycystic ovarian morphology with fasting hyperinsulinemia
EElevated free testosterone with an elevated fasting insulin level
Reveal answer & full explanation
Correct answer: C — Oligo-ovulation with clinical or biochemical hyperandrogenism
AOligo-ovulation with an elevated LH to FSH ratio above 2
BHirsutism with an elevated serum free testosterone level
COligo-ovulation with clinical or biochemical hyperandrogenism✓
DPolycystic ovarian morphology with fasting hyperinsulinemia
EElevated free testosterone with an elevated fasting insulin level
Why Oligo-ovulation with clinical or biochemical hyperandrogenism is correct
Polycystic ovary syndrome (PCOS) is diagnosed by the Rotterdam criteria, which require at least two of three features after excluding mimics: (1) oligo- or anovulation, (2) clinical or biochemical hyperandrogenism, and (3) polycystic ovarian morphology on ultrasound.
This patient has cycles longer than 35 days (oligo-ovulation), hirsutism with elevated free testosterone (hyperandrogenism), and polycystic morphology — meeting all three criteria.
Oligo-ovulation combined with clinical or biochemical hyperandrogenism satisfies the required two-of-three even if the ovaries appeared normal on ultrasound, establishing the diagnosis.
Why the others are wrong
Polycystic ovarian morphology with fasting hyperinsulinemia — polycystic morphology supplies one Rotterdam criterion, but hyperinsulinemia is not a criterion at all, so this pairing still yields only one of the two required features.
Oligo-ovulation with an elevated LH to FSH ratio above 2 — an elevated LH:FSH ratio is a frequently observed laboratory finding in PCOS but is not one of the three Rotterdam criteria, so oligo-ovulation stands alone here and a single criterion is never sufficient.
Elevated free testosterone with an elevated fasting insulin level — insulin resistance is common in PCOS but is not a Rotterdam criterion; this pairing supplies only one true criterion (hyperandrogenism) and therefore cannot confirm the diagnosis.
Hirsutism with an elevated serum free testosterone level — tempting because this patient has both findings, but hirsutism and elevated free testosterone are the clinical and biochemical expressions of the same Rotterdam criterion (hyperandrogenism), so together they still count as only one of the two required features.
Additional high-yield points
Essential exclusions before applying the Rotterdam criteria include congenital adrenal hyperplasia (assessed with 17-hydroxyprogesterone), thyroid disease (TSH), and hyperprolactinemia — all ruled out in this case.
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Endometrial biopsy if prolonged amenorrhea or abnormal bleeding (rule out hyperplasia)
Imaging
Transvaginal pelvic ultrasound: ≥20 follicles per ovary (2-9 mm) and/or ovarian volume ≥10 mL in either ovary; in adults, an elevated serum AMH can be used instead of ultrasound to define PCOM (2023 international guideline)
Ultrasound morphology is NOT required if irregular menses + hyperandrogenism present; also not used in adolescents within 8 years of menarche
Diagnostic algorithm
Domain
Finding
Workup
Ovulatory dysfunction
Oligomenorrhea (<8 cycles/yr) or amenorrhea
Cycle history; progesterone if uncertain
Hyperandrogenism (clinical)
Hirsutism, acne, androgenic alopecia
Modified Ferriman-Gallwey score
Hyperandrogenism (biochemical)
Elevated total/free testosterone, DHEAS
Morning total + free testosterone, SHBG
Polycystic morphology
≥20 follicles/ovary or volume ≥10 mL
Transvaginal ultrasound (not in adolescents)
Exclude mimics
Normal TSH, prolactin, 17-OHP, cortisol
TSH, prolactin, 17-OHP, dexamethasone suppression if indicated
Rotterdam criteria for PCOS — 2 of 3 features required after exclusion of mimics.
Treatment
First-line
Lifestyle modification: 5-10% weight loss restores ovulation in many; Mediterranean-style diet, 150 min/wk moderate exercise
Combined oral contraceptive (COCP) — ethinyl estradiol/levonorgestrel, drospirenone, or norethindrone — for menstrual regulation, hirsutism, acne; protects endometrium
Metformin — improves insulin sensitivity, modest weight loss, restores ovulation in some; first-line for impaired glucose tolerance
Infertility / ovulation induction
Letrozole — first-line (superior live birth vs clomiphene in PCOS per PPCOS II trial)
Clomiphene citrate — second-line
Gonadotropins or IVF if oral agents fail
Hirsutism
COCP × 6 months before judging response
Add spironolactone 50-200 mg/day (anti-androgen) — must be paired with reliable contraception (teratogen)
Eflornithine cream for facial hair; mechanical/laser hair removal as adjunct
Endometrial protection if COCP contraindicated
Cyclic progestin (medroxyprogesterone 5-10 mg × 10-14 days every 1-3 months)
Levonorgestrel IUD
Second-line / adjunct
GLP-1 receptor agonists (semaglutide, liraglutide) for weight loss in obese patients
Metabolic/bariatric surgery for BMI ≥35, or BMI 30-34.9 with metabolic disease (ASMBS/IFSO 2022)
Letrozole has replaced clomiphene as first-line for ovulation induction in PCOS-associated infertility.
Spironolactone is teratogenic (feminization of male fetus) — always combine with effective contraception.
Adolescent diagnosis requires BOTH hyperandrogenism AND irregular cycles defined by time since menarche (1-3 years post-menarche: <21 or >45 days; >3 years: <21 or >35 days; any single cycle >90 days after the first year); ultrasound morphology should not be used.
Screen all PCOS patients for diabetes with a 2-h OGTT (more sensitive than A1c or fasting glucose alone) every 1-3 years.
Prolonged amenorrhea (>3 months) warrants either withdrawal bleed induction with progestin or endometrial sampling.
References
International PCOS Guideline 2023 — 2023 International Evidence-Based Guideline for the Assessment and Management of Polycystic Ovary Syndrome (Teede et al., Fertil Steril 2023)
PPCOS II — Letrozole versus Clomiphene for Infertility in the Polycystic Ovary Syndrome (Legro et al., NEJM 2014)
PMOS consensus 2026 — Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process (Teede et al., Lancet 2026;407:2329-2339)
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