Polycystic Ovary Syndrome (PCOS / PCOD) — High-Yield Notes

Based on international evidence-based guidelines, Endocrine Society, ACOG, and peer-reviewed literature. (NCBI)

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Definition

• PCOS = common endocrine-metabolic disorder in reproductive-age women
• Characterized by:
  • Hyperandrogenism
  • Ovulatory dysfunction
  • Polycystic ovarian morphology
• Associated with:
  • Insulin resistance
  • Obesity
  • Infertility
  • Metabolic syndrome

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Etiopathogenesis

Multifactorial Disorder

• Genetic predisposition
• Environmental factors
• Hormonal dysregulation
• Insulin resistance

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Core Pathophysiology

1. Increased LH secretion

• ↑ GnRH pulse frequency → preferential LH secretion
• ↑ LH stimulates theca cells
• ↑ androgen production

2. Insulin resistance

• Present in many patients (even lean PCOS)
• Hyperinsulinemia:
  • Stimulates ovarian androgen synthesis
  • Suppresses SHBG production in liver
  • ↑ free testosterone

3. Follicular arrest

• Failure of dominant follicle maturation
• Multiple immature follicles accumulate

4. Hyperandrogenism

• Causes:
  • Hirsutism
  • Acne
  • Alopecia
  • Menstrual irregularity

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Diagnostic Criteria (Rotterdam Criteria)

Diagnosis requires 2 out of 3 after excluding other causes: (NCBI)

A. Ovulatory Dysfunction

• Oligomenorrhea
• Amenorrhea
• Anovulation

Menstrual abnormalities

• Cycle >35 days
• <8 cycles/year

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B. Hyperandrogenism

Clinical

• Hirsutism
• Acne
• Androgenic alopecia

Biochemical

• ↑ Total testosterone
• ↑ Free testosterone
• ↑ DHEAS

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C. Polycystic Ovarian Morphology (USG)

• ≥20 follicles per ovary OR
• Ovarian volume >10 mL

Classic appearance

• “String of pearls”

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Important Diagnostic Point

• PCOS is a diagnosis of exclusion. (OUP Academic)

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Differential Diagnoses to Exclude

Endocrine causes

• Hypothyroidism
• Hyperprolactinemia
• Cushing syndrome
• Congenital adrenal hyperplasia
• Androgen-secreting tumors

Others

• Acromegaly
• Premature ovarian insufficiency

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Clinical Features

Menstrual

• Oligomenorrhea
• Amenorrhea
• Irregular cycles
• Infertility

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Hyperandrogenic Features

• Hirsutism
• Acne
• Alopecia
• Seborrhea

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Metabolic Features

• Obesity
• Central obesity
• Insulin resistance
• Acanthosis nigricans

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Reproductive Features

• Subfertility/infertility
• Recurrent miscarriage

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Psychological Associations

• Anxiety
• Depression
• Eating disorders
• Poor body image

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Investigations

Hormonal Tests

• Total/free testosterone
• DHEAS
• LH, FSH
• Prolactin
• TSH
• 17-hydroxyprogesterone

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Metabolic Screening

• Fasting glucose
• HbA1c
• Lipid profile
• OGTT (high-risk patients)

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Imaging

• Pelvic ultrasonography

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Typical Laboratory Findings

• ↑ LH:FSH ratio (>2:1 sometimes)
• ↑ Testosterone
• ↑ Insulin
• ↓ SHBG

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Complications

Reproductive

• Infertility
• Anovulation
• Pregnancy complications

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Metabolic

• Type 2 diabetes mellitus
• Dyslipidemia
• Metabolic syndrome
• Hypertension

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Cardiovascular

• Increased long-term CV risk

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Endometrial

• Endometrial hyperplasia
• Endometrial carcinoma
  • Due to chronic unopposed estrogen

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Management

1. Lifestyle Modification (First-line)

• Weight reduction
• Exercise
• Calorie restriction
• Low glycemic diet

Benefits

• Improves ovulation
• Reduces insulin resistance
• Improves fertility

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2. Menstrual Irregularity Management

Combined Oral Contraceptive Pills (COCPs)

• First-line for nonfertility symptoms
• Benefits:
  • Regular cycles
  • ↓ androgen production
  • Improves acne/hirsutism

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3. Hirsutism & Acne

Antiandrogens

• Spironolactone
• Finasteride
• Flutamide (rare due to hepatotoxicity)

Important

• Use contraception with antiandrogens

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4. Insulin Resistance

Metformin

• Improves insulin sensitivity
• May restore ovulation
• Useful in:
  • Obesity
  • Prediabetes
  • Metabolic syndrome

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5. Infertility Treatment

First-line Ovulation Induction

• Letrozole (preferred)
• Clomiphene citrate

Others

• Gonadotropins
• IVF if resistant

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Pregnancy Risks in PCOS

• Gestational diabetes
• Pregnancy-induced hypertension
• Preeclampsia
• Preterm birth

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Adolescent PCOS

• Diagnosis difficult soon after menarche
• Physiologic irregular cycles common
• Ultrasound less reliable in adolescents (NCBI)

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High-Yield Exam Pearls

• Most accepted criteria = Rotterdam criteria
• Need 2 out of 3 criteria
• PCOS is a diagnosis of exclusion
• Most common cause of anovulatory infertility
• Insulin resistance is central mechanism
• Chronic anovulation → unopposed estrogen → endometrial cancer risk
• First-line treatment = lifestyle modification
• First-line ovulation induction = letrozole
• COCPs are first-line for menstrual symptoms
• “String of pearls” appearance on USG

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Very Short Summary

PCOS is a common endocrine disorder characterized by:

• Hyperandrogenism
• Irregular ovulation
• Polycystic ovaries

Main problems:

• Irregular periods
• Infertility
• Hirsutism
• Obesity
• Insulin resistance

Treatment:

• Lifestyle change
• COCPs
• Metformin
• Letrozole for fertility

Renaming PCOS to PMOS

Yes — there has been a major recent international change in terminology.

New Name for PCOS

The condition previously called PCOS (Polycystic Ovary Syndrome) has officially been renamed:

PMOS

Polyendocrine Metabolic Ovarian Syndrome

This was announced in 2026 after a 14-year international consensus effort involving:

• Endocrinologists
• Gynecologists
• Researchers
• Patient advocacy groups
• More than 50 global medical organizations (The Guardian)

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Why Was the Name Changed?

Experts felt the term “PCOS” was misleading because:

• Many patients do not actually have ovarian cysts
• The disorder affects multiple body systems, not only ovaries
• The old name caused:
  • Delayed diagnosis
  • Confusion
  • Stigma
  • Under-recognition of metabolic disease

The new term “PMOS” better reflects:

• Endocrine dysfunction
• Metabolic abnormalities
• Hormonal imbalance
• Reproductive effects (The Guardian)

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Full Form Breakdown

P — Polyendocrine

Multiple hormone systems are involved

M — Metabolic

Strong association with:

• Insulin resistance
• Obesity
• Diabetes
• Dyslipidemia

O — Ovarian

Ovarian dysfunction and ovulatory problems remain important

S — Syndrome

Collection of related clinical features

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Important Clinical Point

Diagnostic criteria remain essentially the same.

The name changed, but the underlying disorder and diagnostic approach remain based on established international criteria. (The Cut)

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Key Facts

• Affects approximately 1 in 8 women worldwide
• Estimated >170 million affected globally
• Strongly associated with:
  • Infertility
  • Metabolic syndrome
  • Type 2 diabetes
  • Cardiovascular risk
  • Mental health disorders (endocrine.org)

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Transition Timeline

International organizations plan gradual adoption of the term PMOS in:

• Clinical guidelines
• Research papers
• Medical education
• Public awareness campaigns

Implementation is expected over the next few years. (The Guardian)