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usmle step 2 ck

Polycystic Ovary Syndrome

Common endocrine disorder causing ovulatory dysfunction and hyperandrogenism, associated with insulin resistance, infertility, endometrial hyperplasia, and metabolic syndrome

Review date
reviewed 2026-05-04
Reading time
8 min read
Author
Dr Kola Tytler MBBS CertHE MBA MSt MRCGP
Obstetrics & Gynecologycommonlong-term-condition
On this page
Condition details
Obstetrics & Gynecology
common
8 min read
reviewed 2026-05-04
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About This Page

This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.

Key points

  • PCOS = hyperandrogenism plus ovulatory dysfunction after excluding mimics
  • Symptoms include oligomenorrhea/amenorrhea, hirsutism, acne, infertility, obesity, insulin resistance
  • Exclude pregnancy, thyroid disease, hyperprolactinemia, nonclassic CAH, androgen tumor, and Cushing when indicated
  • First-line for menstrual regulation/hirsutism when not trying to conceive: combined oral contraceptives
  • Infertility treatment often uses letrozole for ovulation induction

Overview

PCOS is characterized by ovulatory dysfunction and androgen excess. Chronic anovulation causes unopposed estrogen exposure and increases risk of endometrial hyperplasia/cancer. Step 2 CK tests irregular menses + hirsutism and treatment based on pregnancy goals.

Epidemiology

PCOS is one of the most common causes of anovulatory infertility. Long-term complications include type 2 diabetes, dyslipidemia, metabolic syndrome, obstructive sleep apnea, infertility, pregnancy complications, and endometrial hyperplasia.

Clinical Features

Symptoms
Oligomenorrhea, amenorrhea, or irregular bleeding
Hirsutism, acne, androgenic alopecia
Infertility due to anovulation
Weight gain or difficulty losing weight
Rapid virilization suggests androgen-secreting tumor
Signs
Hirsutism in androgen-sensitive areas
Acanthosis nigricans suggests insulin resistance
Elevated BMI or central adiposity
Normal pelvic exam is common
Marked virilization requires urgent androgen evaluation

Investigations

First-line
Pregnancy testAlways exclude pregnancy in amenorrhea
TSH and prolactinExclude thyroid disease and hyperprolactinemia
Total/free testosterone and DHEA-SVery high values suggest ovarian/adrenal tumor
Second-line
17-hydroxyprogesteroneScreens for nonclassic CAH
Metabolic screeningHbA1c or OGTT, lipid profile, BP, BMI
Pelvic ultrasoundPolycystic morphology supports diagnosis but is not always required
Specialist
Endocrinology or reproductive endocrinology referralSevere hyperandrogenism, infertility, uncertain diagnosis, treatment resistance
Endometrial samplingPersistent AUB or prolonged unopposed estrogen risk factors

Management

ACOG Practice Bulletin: Polycystic Ovary Syndrome
1
Not seeking pregnancy
  • Combined OCPs first-line for menstrual regulation, endometrial protection, acne, hirsutism
  • Cyclic progestin or progestin IUD if estrogen contraindicated
  • Spironolactone can be added for hirsutism after reliable contraception
  • Cosmetic hair removal/topical eflornithine/acne therapies adjunctive
2
Metabolic management
  • Lifestyle and weight loss when overweight
  • Screen/treat dyslipidemia, hypertension, glucose intolerance, sleep apnea
  • Metformin for impaired glucose tolerance/diabetes risk and cycle improvement
3
Seeking pregnancy
  • Letrozole commonly first-line ovulation induction
  • Clomiphene alternative
  • Weight optimization improves ovulation and outcomes
  • Screen early for diabetes if high-risk and repeat routine GDM screen as needed

Complications

  • Endometrial hyperplasia/cancer: Chronic anovulation causes unopposed estrogen
  • Infertility: Oligo-ovulation/anovulation
  • Type 2 diabetes: Insulin resistance
  • Metabolic syndrome: Dyslipidemia, hypertension, central obesity
  • Pregnancy complications: GDM, hypertensive disorders, preterm birth
USMLE Step 2 CK Exam Tips
  • 1Irregular menses + hirsutism/acne + obesity/acanthosis = PCOS
  • 2Always exclude pregnancy, TSH abnormality, and hyperprolactinemia
  • 3High LH:FSH ratio is classic but not required/best test
  • 4First-line if not trying to conceive = combined OCP
  • 5Endometrial protection is essential
  • 6Trying to conceive = letrozole
  • 7Rapid virilization or very high androgen levels = tumor, not PCOS

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regional clinical guidance

Polycystic Ovary Syndrome: guidance by region

Recommendations, thresholds and pathways can differ. Open the page written for the jurisdiction you need.

United StatesPolycystic ovary syndromeWomen's health · reviewed 2026-08-20

Verified Sources & References

ACOG Practice Bulletin — Polycystic Ovary Syndrome
ACOG Patient FAQ — PCOS
ASRM Practice Guidance
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