Polycystic Ovarian Syndrome (PCOS)

1. Clinical Overview

Summary

Polycystic Ovarian Syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, affecting approximately 8-13% of this population worldwide. [1] It is a complex heterogeneous condition characterised by reproductive, metabolic, and psychological features. The hallmark presentation involves oligo-anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound, though not all features need to be present for diagnosis. [2]

PCOS is not merely a gynaecological disorder—it represents a systemic metabolic condition with profound implications for cardiovascular health, glucose metabolism, and long-term cancer risk. Insulin resistance is present in approximately 70% of obese women and 30-40% of lean women with PCOS, serving as a key pathophysiological driver. [3] This insulin resistance stimulates ovarian androgen production, suppresses sex hormone-binding globulin (SHBG) synthesis, and contributes to the clinical manifestations of the syndrome.

The condition carries significant long-term health implications: women with PCOS have a 4-fold increased risk of developing type 2 diabetes mellitus, a 2-fold increased risk of metabolic syndrome, elevated cardiovascular disease risk, and a 3-fold increased risk of endometrial cancer due to unopposed oestrogen exposure. [4,5] Early recognition and holistic management are essential to mitigate these risks.

Key Facts

Prevalence and Impact:

• Affects 1 in 10-12 women of reproductive age globally
• Accounts for approximately 75% of anovulatory infertility cases [6]
• Present in up to 80% of women with hirsutism [7]
• Estimated healthcare costs exceed $4 billion annually in the United States alone

Pathophysiological Principles:

• Insulin Resistance: Hyperinsulinaemia acts as a co-gonadotrophin, directly stimulating ovarian theca cells to produce androgens via upregulation of cytochrome P450c17α enzyme activity
• SHBG Suppression: Insulin inhibits hepatic production of SHBG, resulting in increased free (bioavailable) testosterone despite potentially normal total testosterone levels
• LH Hypersecretion: Altered hypothalamic GnRH pulse frequency leads to preferential LH secretion over FSH, with LH:FSH ratios often > 2:1 or 3:1
• Arrested Follicular Development: Excess androgens and abnormal LH:FSH ratios prevent normal follicular maturation, resulting in multiple small antral follicles (2-9mm) visible on ultrasound

Fertility Considerations:

• Despite anovulation, women with PCOS typically have abundant ovarian reserve
• Respond well to ovulation induction therapies
• May have increased risk of ovarian hyperstimulation syndrome (OHSS) during assisted reproduction due to multiple recruitable follicles [8]
• Pregnancy complications include increased risk of gestational diabetes (odds ratio 2.9), pregnancy-induced hypertension, pre-eclampsia, and preterm delivery [9]

Endometrial Cancer Risk:

• Chronic anovulation leads to unopposed oestrogen stimulation of the endometrium
• Women with amenorrhoea for > 1 year have a 3-fold increased endometrial cancer risk [5]
• Risk is mediated by obesity, insulin resistance, and lack of progesterone-induced differentiation
• Regular withdrawal bleeds (minimum every 3-4 months) provide endometrial protection

Clinical Pearls

PCO vs PCOS - Critical Distinction: Polycystic ovaries (PCO) on ultrasound are found in 20-30% of women of reproductive age and represent a morphological finding, NOT a disease. [10] PCO becomes PCOS only when accompanied by ovulatory dysfunction and/or hyperandrogenism. Many women with polycystic ovarian morphology have regular ovulatory cycles, normal hormones, and no metabolic disturbance—they do NOT have PCOS and should not be labelled or treated as such.

Virilisation is a Red Flag: Hirsutism (excess terminal hair in androgen-sensitive areas) affects 60-70% of women with PCOS and is expected. However, virilisation (deep voice, male-pattern temporal balding, clitoromegaly > 10mm, rapid muscle development) is NOT a feature of PCOS. Virilisation suggests an androgen-secreting tumour (ovarian or adrenal) or severe Cushing's syndrome. Testosterone levels > 5 nmol/L (> 150 ng/dL) warrant urgent imaging and endocrinology referral. [11]

Weight Loss - The Single Most Effective Intervention: Loss of just 5-10% of body weight can restore regular ovulation in 50-60% of overweight/obese women with PCOS without any pharmacotherapy. [12] Weight reduction improves insulin sensitivity, reduces hyperinsulinaemia, lowers free androgen levels, and restores normal hypothalamic-pituitary-ovarian axis function. This should be the foundation of management in all overweight patients before escalating to medication.

The "Lean PCOS" Phenotype: Approximately 20-30% of women with PCOS have a BMI less than 25 kg/m². [13] These women may have milder metabolic disturbance but still experience significant reproductive symptoms, hirsutism, and long-term health risks. Management strategies differ—weight loss is not the primary intervention, and insulin-sensitising agents may have limited benefit. They require individualised treatment approaches.

---

2. Epidemiology

Global Prevalence

The reported prevalence of PCOS varies considerably depending on the diagnostic criteria applied and the population studied. Using the Rotterdam criteria (most widely adopted), the global prevalence is estimated at 8-13% of women of reproductive age. [1] Some studies report prevalence as high as 18-21% when using ultrasound criteria more liberally.

Diagnostic Criteria Impact on Prevalence

Demographics

Age Distribution:

• Onset typically occurs around menarche, though diagnosis is often delayed by 5-10 years
• Symptoms may become apparent in late adolescence or early adulthood
• Reproductive symptoms (irregular cycles, infertility) most prominent in reproductive years
• Metabolic manifestations persist and often worsen post-menopause

Ethnic Variations: Women of South Asian, Middle Eastern, and Hispanic descent have higher prevalence and more severe metabolic phenotypes with earlier onset of insulin resistance and type 2 diabetes. [14] African American women demonstrate higher prevalence of metabolic features but may have lower rates of polycystic ovarian morphology on ultrasound.

Genetic Predisposition: PCOS demonstrates familial clustering with heritability estimated at 70%. [15] First-degree female relatives have a 20-40% risk of developing PCOS. Multiple susceptibility genes have been identified involving insulin signalling pathways, androgen biosynthesis, and gonadotrophin regulation.

Risk Factors

Temporal Trends

PCOS diagnosis has increased substantially over the past 30 years, partly due to improved recognition and broader diagnostic criteria (Rotterdam), but also potentially due to rising obesity rates globally. The condition is now recognised as one of the leading causes of female infertility and a major contributor to metabolic disease burden in reproductive-age women.

---

3. Aetiology & Pathophysiology

PCOS is a multifactorial disorder arising from complex interactions between genetic predisposition, intrauterine environment, and postnatal lifestyle factors. No single unifying defect has been identified; rather, it represents a final common pathway of multiple pathophysiological disturbances.

Primary Mechanisms

1. Hypothalamic-Pituitary Dysfunction

Altered GnRH Pulsatility: Normal menstrual cyclicity requires coordinated pulsatile GnRH release from the hypothalamus. In PCOS, GnRH pulse frequency is abnormally increased, favouring LH synthesis and secretion over FSH. [16]

• Elevated LH: Persistently high LH stimulates ovarian theca cells to produce excessive androgens (androstenedione and testosterone)
• Relative FSH Deficiency: Insufficient FSH prevents normal follicular recruitment, growth, and selection of a dominant follicle
• Arrested Follicular Development: Multiple small antral follicles (2-9mm) accumulate but fail to mature beyond this stage, creating the characteristic "polycystic" appearance on ultrasound
• LH:FSH Ratio: Classic teaching suggests ratio > 2:1 or 3:1, though this is neither sensitive nor specific and is not required for diagnosis

2. Insulin Resistance and Hyperinsulinaemia

Insulin resistance is a hallmark feature present in 50-80% of women with PCOS (higher in obese, but present in 30-40% of lean PCOS). [3]

Mechanisms of Insulin-Driven Hyperandrogenism:

1. Direct Ovarian Stimulation: Insulin and IGF-1 receptors are present on ovarian theca cells. Hyperinsulinaemia acts synergistically with LH to upregulate the enzyme cytochrome P450c17α (17α-hydroxylase), increasing androgen biosynthesis. [17]

2. Hepatic SHBG Suppression: Insulin inhibits hepatic production of sex hormone-binding globulin (SHBG). Lower SHBG levels result in increased free (bioavailable) testosterone, even when total testosterone is only mildly elevated or normal.

3. IGF-1 System Dysregulation: Insulin suppresses hepatic production of IGF-binding protein-1 (IGFBP-1), increasing free IGF-1, which further amplifies ovarian androgen production.

4. Adipose Tissue Dysfunction: Visceral adiposity promotes inflammatory cytokine release (TNF-α, IL-6) and altered adipokine secretion (reduced adiponectin, increased leptin), worsening insulin resistance in a vicious cycle.

Selective Insulin Resistance: Intriguingly, while metabolic insulin signalling is impaired (glucose uptake), mitogenic pathways remain intact or enhanced. This explains why hyperinsulinaemia continues to drive androgen production and other proliferative effects despite peripheral insulin resistance. [18]

3. Ovarian Hyperandrogenism

Excess ovarian androgen production is central to PCOS pathophysiology:

• Theca Cell Dysfunction: Intrinsic theca cell hyperactivity with increased expression of steroidogenic enzymes
• Androgen Effects on Folliculogenesis: High intra-ovarian androgens disrupt normal follicular development, cause premature follicular atresia, and prevent dominant follicle selection
• Peripheral Conversion: Androgens are peripherally converted to oestrogens (primarily oestrone) in adipose tissue, contributing to unopposed oestrogen effects on the endometrium

4. Chronic Low-Grade Inflammation

Women with PCOS exhibit elevated markers of inflammation:

• Increased C-reactive protein (CRP)
• Elevated inflammatory cytokines (IL-6, TNF-α)
• Increased oxidative stress markers

This inflammatory state contributes to insulin resistance, endothelial dysfunction, and potentially increased cardiovascular risk. [19]

Genetic and Epigenetic Factors

PCOS is highly heritable (70%), suggesting strong genetic contribution. Genome-wide association studies (GWAS) have identified multiple susceptibility loci involving:

• Gonadotrophin signalling (LHCGR, FSHR)
• Insulin signalling and glucose homeostasis (INSR, IRS1)
• Androgen biosynthesis and metabolism (CYP11A1, CYP17A1)
• Obesity and adiposity regulation (FTO)

Epigenetic modifications (DNA methylation, histone modifications) may also contribute, potentially explaining intrauterine programming effects observed in offspring of mothers with gestational diabetes or PCOS.

Environmental and Developmental Factors

Intrauterine Programming: Exposure to excess androgens or metabolic disturbances in utero may predispose to PCOS development:

• Daughters of women with PCOS have 5-fold increased risk
• Animal models show that prenatal androgen exposure reproduces PCOS-like phenotype
• Gestational diabetes and maternal obesity increase offspring PCOS risk

Postnatal Influences:

• Premature adrenarche (early development of pubic hair before age 8)
• Childhood obesity
• Rapid weight gain during adolescence
• Endocrine-disrupting chemicals (bisphenol A, phthalates) - emerging evidence of association

Integrated Pathophysiological Model

GENETIC PREDISPOSITION + ENVIRONMENTAL FACTORS
              ↓
    INSULIN RESISTANCE ←→ OBESITY
              ↓                ↓
    HYPERINSULINAEMIA    INFLAMMATION
         ↓           ↓         ↓
    ↓ SHBG      OVARIAN      ↑ LH
                ANDROGENS   SECRETION
         ↓           ↓         ↓
      ↑ FREE TESTOSTERONE
              ↓
    ┌─────────┼─────────┐
    ↓         ↓         ↓
HIRSUTISM  ANOVULATION  METABOLIC
ACNE      INFERTILITY   DYSFUNCTION

---

4. Clinical Presentation

Rotterdam Criteria (2003) - Diagnostic Standard

Diagnosis requires 2 of the following 3 criteria (after exclusion of other aetiologies):

1. Oligo-ovulation or Anovulation

   • Irregular menstrual cycles (typically > 35 days or less than 21 days)
   • less than 9 periods per year
   • Amenorrhoea (absence of menses for > 3 months in previously menstruating woman)

2. Clinical or Biochemical Hyperandrogenism

   • Clinical: Hirsutism (Ferriman-Gallwey score ≥4-6 depending on ethnicity), acne, androgenic alopecia
   • Biochemical: Elevated serum androgens (total testosterone, free testosterone, androstenedione, DHEAS)

3. Polycystic Ovaries on Ultrasound

   • ≥20 follicles (2-9mm diameter) per ovary, OR
   • Ovarian volume > 10mL (calculated by 0.5 × length × width × thickness)
   • Note: Updated 2013 criterion requires ≥20 follicles using modern high-resolution ultrasound; original 2003 criterion was ≥12 follicles

Important Exclusion Criteria: Must exclude other causes of hyperandrogenism and ovulatory dysfunction:

• Congenital adrenal hyperplasia (21-hydroxylase deficiency)
• Androgen-secreting tumours (ovarian, adrenal)
• Cushing's syndrome
• Hyperprolactinaemia
• Thyroid dysfunction
• Primary hypothalamic amenorrhoea

PCOS Phenotypes

The Rotterdam criteria create four possible phenotypes:

Phenotype A and B (NIH criteria) have the most severe metabolic features, while phenotype D has the mildest metabolic disturbance but still carries reproductive and long-term health implications.

Reproductive Features

Menstrual Irregularity:

• Oligomenorrhoea (cycles > 35 days): Most common presentation
• Amenorrhoea (absence of menses): Seen in 20-30%
• Occasional dysfunctional uterine bleeding due to unopposed oestrogen
• Some women have regular cycles but are anovulatory (detected only through progesterone measurement or fertility investigations)

Infertility:

• PCOS accounts for 75% of anovulatory infertility cases
• However, many women with PCOS conceive spontaneously, particularly if ovulatory
• Infertility presentation typically occurs in late 20s-30s when actively attempting conception

Hyperandrogenic Features

Hirsutism (60-80% of women with PCOS):

• Excess terminal hair growth in male-pattern distribution (face, chest, abdomen, back, inner thighs)
• Quantified using Ferriman-Gallwey Score: assesses 9 body areas, each scored 0-4 (maximum 36)
  • "Score ≥8: Abnormal in Caucasian/African populations"
  • "Score ≥4-6: Abnormal in Asian populations (ethnic variation important)"
• Hair growth is progressive without treatment
• Temporal lag: hirsutism worsens 6-12 months after androgen elevation due to hair growth cycle

Acne:

• Moderate to severe acne persisting beyond adolescence (> 25 years old)
• Typically affects face, chest, and back
• May be refractory to conventional dermatological therapies
• Androgen-mediated sebaceous gland stimulation

Androgenic Alopecia:

• Male-pattern hair loss (frontal/temporal recession, crown thinning)
• Diffuse thinning over vertex
• Less common than hirsutism (affects 10-20%)

Acanthosis Nigricans:

• Velvety, hyperpigmented thickening of skin in intertriginous areas (neck, axillae, groin, under breasts)
• Marker of severe insulin resistance, not hyperandrogenism per se
• Associated with higher diabetes risk

Metabolic Features

Obesity:

• Present in 40-60% of women with PCOS in Western populations (lower in Asian populations)
• Predominantly central/visceral adiposity ("apple-shaped")
• Exacerbates insulin resistance and hyperandrogenism
• Not required for diagnosis—20-30% of women with PCOS are lean

Insulin Resistance:

• Clinically silent but detectable through laboratory testing
• May manifest as impaired fasting glucose, impaired glucose tolerance, or overt type 2 diabetes
• Acanthosis nigricans serves as clinical marker

Metabolic Syndrome:

• Prevalence 33-47% in women with PCOS (vs 6% in age-matched controls) [20]
• Defined by ≥3 of: central obesity, elevated triglycerides, low HDL, hypertension, impaired fasting glucose

Psychological Features

Women with PCOS have significantly elevated rates of:

• Depression (odds ratio 3-4×)
• Anxiety disorders (odds ratio 3-5×)
• Eating disorders, particularly binge eating
• Poor body image and reduced quality of life
• These associations persist even after controlling for BMI [21]

Mechanisms likely multifactorial: hormonal effects on mood, psychological impact of hirsutism/infertility, chronic disease burden, and societal pressures.

---

5. Clinical Examination

General Inspection

• Body Habitus: Assess body mass index (BMI), waist circumference, central vs peripheral fat distribution
• Virilisation Signs: Deep voice, increased muscle bulk, clitoromegaly—RED FLAGS requiring urgent investigation
• Skin: Look for acne distribution, acanthosis nigricans, skin tags (associated with insulin resistance)

Hirsutism Assessment

Ferriman-Gallwey Scoring: Score 9 androgen-sensitive areas (0-4 each):

1. Upper lip
2. Chin
3. Chest
4. Upper back
5. Lower back
6. Upper abdomen
7. Lower abdomen
8. Upper arms
9. Thighs

• Interpretation: ≥8 abnormal (Caucasian); ≥4-6 abnormal (Asian ethnicity)
• Documentation: Important for monitoring treatment response
• Limitation: Subjective; affected by cosmetic hair removal

Anthropometric Measurements

• Weight and Height: Calculate BMI
• Waist Circumference: > 88cm in women indicates central obesity and increased metabolic risk
• Blood Pressure: Screen for hypertension (associated with metabolic syndrome)

Gynaecological Examination

• External Genitalia: Assess for clitoromegaly (> 10mm suggests virilisation)
• Pelvic Examination: Generally not contributory for PCOS diagnosis itself, but consider if abnormal bleeding to exclude other pathology
• Bimanual Examination: Ovaries may be palpably enlarged (though polycystic ovaries themselves are not necessarily larger)

Dermatological Examination

• Acne: Severity, distribution, scarring
• Alopecia: Ludwig scale for female pattern hair loss (Grade I-III)
• Acanthosis Nigricans: Presence and severity (neck, axillae, groin, inframammary)

---

6. Investigations

Essential Exclusion Tests

Before diagnosing PCOS, alternative causes of hyperandrogenism and oligo-anovulation must be excluded:

Hormonal Assessment

Timing: Ideally performed on day 2-5 of menstrual cycle (early follicular phase). If amenorrhoeic, can be performed at any time or after progesterone-induced withdrawal bleed.

Androgens:

Gonadotrophins:

Important Note: LH:FSH ratio is often taught as diagnostic, but only present in 40-50% of PCOS cases. Diagnosis does not depend on this ratio.

Metabolic Screening

Glucose Homeostasis:

All women with PCOS should be screened for impaired glucose tolerance and diabetes:

• Fasting Glucose: Screening test
• HbA1c: Alternative screening test (≥48 mmol/mol or ≥6.5% indicates diabetes)
• 75g Oral Glucose Tolerance Test (OGTT): Gold standard
  • "Recommended in all women with PCOS who have additional risk factors: BMI > 25, family history of diabetes, previous gestational diabetes, South Asian/Middle Eastern ethnicity"
  • "Impaired glucose tolerance: 2-hour glucose 7.8-11.0 mmol/L"
  • "Diabetes: 2-hour glucose ≥11.1 mmol/L"
• Repeat screening: Every 2-3 years, more frequently if impaired glucose tolerance

Lipid Profile:

• Total cholesterol, LDL, HDL, triglycerides
• Dyslipidaemia common in PCOS: elevated triglycerides, low HDL cholesterol
• Increased cardiovascular risk profile

Imaging

Transvaginal Pelvic Ultrasound (Gold Standard for Ovarian Assessment):

Polycystic Ovary Morphology Criteria (2013 update):

• ≥20 follicles measuring 2-9mm diameter in at least one ovary, OR
• Ovarian volume > 10mL in at least one ovary (without corpus luteum, cyst, or dominant follicle)

Technical Considerations:

• Perform in early follicular phase (day 3-5) if cycles present
• Use high-resolution transvaginal ultrasound (endovaginal transducers ≥8 MHz)
• If transvaginal ultrasound not possible (virginity, patient preference), transabdominal ultrasound less sensitive but acceptable
• "String of pearls" sign: peripheral distribution of small follicles

Limitations:

• Polycystic ovarian morphology present in 20-30% of normal ovulatory women
• Not diagnostic in isolation
• Should not be used as sole criterion in adolescents (high false-positive rate)

Alternative/Additional Imaging:

• Anti-Müllerian Hormone (AMH): Correlates with follicle count; elevated in PCOS (> 35-40 pmol/L); emerging as potential surrogate for ultrasound, particularly in adolescents
• Adrenal/Ovarian CT or MRI: If androgen-secreting tumour suspected (testosterone > 5 nmol/L, rapid onset virilisation)

Optional Advanced Investigations

---

7. Management

Management of PCOS is individualised based on:

1. Patient's primary concerns (fertility, menstrual regulation, hirsutism, metabolic health)
2. Presence or absence of obesity
3. Metabolic phenotype and comorbidities
4. Patient preferences

Management Algorithm

                    PCOS DIAGNOSIS CONFIRMED
                             ↓
               ┌─────────────┴─────────────┐
               ↓                           ↓
        BMI > 25 kg/m²               BMI less than 25 kg/m²
               ↓                           ↓
    LIFESTYLE MODIFICATION           Proceed to
    (Weight loss 5-10%)          symptom-directed
         Target BMI less than 25              management
               ↓
    ┌──────────┴──────────┬──────────────┬──────────────┐
    ↓                     ↓              ↓              ↓
FERTILITY            MENSTRUAL       HIRSUTISM/     METABOLIC
DESIRED            REGULATION        ACNE           HEALTH
    ↓                     ↓              ↓              ↓
Ovulation         Endometrial     Cosmetic        Screen for
Induction         Protection      + Medical       Diabetes/CVD
    ↓                     ↓              ↓              ↓
1. Letrozole       1. COCP          1. COCP         Metformin
2. Clomiphene      2. Cyclical      2. Topical      (if IGT/IFG)
3. Metformin          Progestogen      Eflornithine
   (adjunct)       3. Mirena IUS    3. Spironolactone  Lifestyle
4. Gonadotropins                    4. Laser/          Statin (if
5. LOD                                 Electrolysis    dyslipidaemia)
6. IVF

1. Lifestyle Modification - Foundation of Management

Weight Loss in Overweight/Obese Women:

Weight reduction of just 5-10% of initial body weight produces clinically significant improvements:

• Restoration of ovulation in 50-60% of anovulatory women [12]
• Reduction in total and free testosterone
• Increase in SHBG
• Improvement in insulin sensitivity
• Improved lipid profile
• Reduction in cardiovascular risk markers
• Enhanced response to ovulation induction therapies

Evidence: A Cochrane review demonstrated that lifestyle interventions (diet and exercise) improve reproductive outcomes, with regular menstruation restored in 50% of women achieving weight loss. [22]

Practical Recommendations:

• Dietary: Caloric deficit of 500-750 kcal/day; low-glycaemic index diet preferred
• Exercise: Minimum 150 minutes of moderate-intensity aerobic activity per week
• Behavioural: Goal-setting, self-monitoring, structured programs
• Multidisciplinary: Dietitian, exercise physiologist, psychologist support

Bariatric Surgery: For women with BMI > 35-40 kg/m² and failure of conservative weight loss, bariatric surgery (laparoscopic sleeve gastrectomy, Roux-en-Y gastric bypass) can produce dramatic metabolic and reproductive improvements, including restoration of ovulation and reversal of metabolic syndrome.

2. Menstrual Regulation and Endometrial Protection

Goal: Induce withdrawal bleed at least every 3-4 months to prevent endometrial hyperplasia and reduce cancer risk.

Combined Oral Contraceptive Pill (COCP) - First Line

Mechanism:

• Suppresses LH secretion → reduces ovarian androgen production
• Increases hepatic SHBG production → lowers free testosterone
• Provides endometrial protection through cyclical progestogen withdrawal
• Regulates menstrual cycle

Choice of Pill:

• Any standard COCP can be used
• Dianette (co-cyprindiol): Ethinylestradiol + cyproterone acetate (potent anti-androgen); particularly effective for hirsutism/acne BUT higher VTE risk—limit to 12-24 months
• Yasmin (drospirenone-containing): Drospirenone has anti-androgenic and anti-mineralocorticoid properties; may be preferred for PCOS
• Standard formulations (e.g., Microgynon, Rigevidon) equally effective for menstrual regulation

Contraindications: Standard COCP contraindications (VTE risk, migraine with aura, > 35 years + smoking, hypertension, BMI > 35 some guidelines)

Cyclical Progestogen

Indication: When oestrogen contraindicated or COCP declined

Regimen:

• Medroxyprogesterone acetate 10mg daily for 12-14 days every 1-3 months
• Norethisterone 5mg twice daily for 10-14 days every 1-3 months
• Induces withdrawal bleed within 2-7 days of completing course

Advantages: Avoids oestrogen; suitable for most women Disadvantages: Does not improve hyperandrogenism; does not provide contraception

Levonorgestrel Intrauterine System (Mirena IUS)

Mechanism: Local endometrial progestogen effect provides continuous endometrial protection without systemic hormone suppression

Advantages:

• Highly effective endometrial protection
• Long-acting (5 years)
• Reduces menstrual bleeding (may cause amenorrhoea)
• Effective contraception

Disadvantages:

• Does not suppress ovarian androgens or improve hirsutism
• Initial irregular bleeding common
• Requires insertion procedure

3. Management of Hyperandrogenism (Hirsutism and Acne)

Combined Oral Contraceptive Pill

Mechanism: As above—suppresses androgens, increases SHBG Timeframe: 6-12 months required for visible improvement in hirsutism (due to hair growth cycle) Most Effective Formulations:

• Dianette (co-cyprindiol): Cyproterone acetate is potent anti-androgen
• Yasmin (drospirenone): Mild anti-androgenic effect

Anti-Androgen Medications

Spironolactone (Aldosterone Antagonist with Anti-Androgen Properties):

• Dose: 50-200mg daily
• Mechanism: Blocks androgen receptors; inhibits 5α-reductase (reduces conversion of testosterone to dihydrotestosterone)
• Efficacy: Reduces Ferriman-Gallwey score by 30-50% over 6-12 months [23]
• Side Effects: Menstrual irregularity, breast tenderness, hyperkalaemia (monitor K+), diuretic effect
• Contraindication: Pregnancy (theoretical feminisation of male fetus)—MUST use contraception
• Contraception Requirement: Usually combined with COCP

Finasteride (5α-Reductase Inhibitor):

• Dose: 5mg daily
• Mechanism: Blocks conversion of testosterone to dihydrotestosterone
• Efficacy: Similar to spironolactone
• Teratogenic: Absolutely contraindicated in pregnancy—feminisation of male fetus; requires reliable contraception
• Less Commonly Used than spironolactone in PCOS

Cyproterone Acetate (Progestogen with Anti-Androgen Activity):

• Available as component of Dianette, or separately
• High-dose regimens (50-100mg) used in some countries but limited in UK due to hepatotoxicity and VTE risk

Topical Treatments

Eflornithine Cream 13.9% (Vaniqa):

• Mechanism: Irreversibly inhibits ornithine decarboxylase, reducing hair growth rate
• Application: Twice daily to affected areas (face)
• Efficacy: Reduces facial hair growth; not curative—hair regrows after discontinuation
• Timeframe: 6-8 weeks for visible effect
• Side Effects: Skin irritation, acne
• Adjunct: Best used alongside other therapies

Cosmetic and Physical Treatments

• Laser Hair Removal: Long-lasting reduction in terminal hair; requires multiple sessions
• Electrolysis: Permanent hair removal; time-intensive
• Shaving, Waxing, Bleaching, Depilatory Creams: Temporary solutions; no impact on hair growth rate
• Important: Medical therapy reduces NEW hair growth but does not remove existing hair—combination of cosmetic and medical approaches most effective

Acne Management

• COCP (especially Dianette)
• Topical retinoids (adapalene, tretinoin)
• Topical antibiotics (clindamycin)
• Oral antibiotics (lymecycline, doxycycline) for moderate-severe acne
• Isotretinoin for severe refractory acne (dermatology referral; highly teratogenic)

4. Fertility Management - Ovulation Induction

First-Line: Letrozole (Aromatase Inhibitor)

Mechanism: Blocks aromatase enzyme → reduces oestrogen synthesis → removes negative feedback on pituitary → increases FSH secretion → stimulates follicle development

Dosing: 2.5-7.5mg daily for days 3-7 of cycle (natural or induced)

Evidence:

• PPCOS II Trial (NEJM 2014): Letrozole superior to clomiphene for live birth rate (27.5% vs 19.1%, p=0.007) in obese women with PCOS [24]
• Now considered first-line by international guidelines (ESHRE/ASRM 2018) [2]

Advantages:

• Higher ovulation rate
• Higher live birth rate
• Lower multiple pregnancy rate compared to clomiphene
• Shorter half-life (fewer anti-oestrogenic effects)

Monitoring: Serial ultrasound follicle tracking recommended to prevent multiple pregnancy; timed intercourse or intrauterine insemination

Second-Line: Clomiphene Citrate (Selective Oestrogen Receptor Modulator)

Mechanism: Blocks hypothalamic oestrogen receptors → increases GnRH and FSH secretion → stimulates follicle development

Dosing: 50-150mg daily for days 2-6 of cycle, up to 6 cycles

Efficacy:

• Ovulation rate: 70-80% of women
• Pregnancy rate: 40-50% over 6 cycles
• Live birth rate: 22-30% over 6 cycles

Limitations:

• Anti-oestrogenic effects on endometrium and cervical mucus (may reduce pregnancy rate despite ovulation)
• Risk of multiple pregnancy (5-10%, mainly twins)
• Visual disturbances (discontinue if occur)

Clomiphene Resistance: Failure to ovulate despite 150mg dose. Occurs in 15-20%, more common in obese women.

Adjunct: Metformin

Mechanism: Improves insulin sensitivity → reduces insulin and androgen levels → may improve ovulation

Dose: 500mg three times daily or 850mg twice daily (or extended-release formulation)

Evidence:

• Metformin alone: Modest improvement in ovulation rates vs placebo
• Metformin + Clomiphene: Combined therapy improves ovulation and pregnancy rates over clomiphene alone in clomiphene-resistant women [25]
• Metformin + Letrozole: Uncertain benefit

Current Role: Adjunct in clomiphene-resistant women; primary role in women with impaired glucose tolerance/type 2 diabetes

Side Effects: Gastrointestinal (diarrhoea, nausea)—start low dose, titrate up; take with food

Note: Metformin use in pregnancy for PCOS remains controversial; some evidence suggests reduced early pregnancy loss and gestational diabetes, but not standard practice.

Third-Line: Gonadotropin Therapy

Indication: Failed oral ovulation induction; clomiphene/letrozole resistance

Agents: Recombinant FSH (follitropin alfa, follitropin beta) or human menopausal gonadotropin (hMG)

Protocol: Low-dose step-up regimen to minimise risk of multiple follicle development and ovarian hyperstimulation syndrome (OHSS)

Monitoring: Essential—frequent ultrasound and oestradiol monitoring; cancel cycle if > 2-3 mature follicles

Risks:

• OHSS: Women with PCOS at HIGH risk due to multiple recruitable follicles (prevalence 5-10% with gonadotropins)
• Multiple pregnancy: 10-20% risk

Setting: Specialist fertility clinic only

Laparoscopic Ovarian Drilling (LOD)

Mechanism: Laparoscopic diathermy or laser destruction of 4-10 points on ovarian surface → reduces androgen-producing stroma → lowers LH and androgens → may restore ovulation

Indication: Clomiphene-resistant PCOS, particularly if laparoscopy required for other reasons (tubal assessment)

Efficacy:

• Ovulation rate: 50-70%
• Pregnancy rate: 40-60% over 6-12 months
• Comparable to gonadotropins but avoids multiple pregnancy and OHSS risk

Advantages:

• Single procedure
• No multiple pregnancy risk
• No need for cycle monitoring
• May restore spontaneous ovulation long-term

Disadvantages:

• Surgical risks (anaesthesia, adhesion formation)
• Potential ovarian damage and reduced ovarian reserve (theoretical, rare)
• Not universally effective

In Vitro Fertilisation (IVF)

Indications:

• Failed ovulation induction therapies
• Concurrent tubal factor or male factor infertility
• Advanced maternal age
• Patient preference

Special Considerations in PCOS:

• High risk of OHSS due to multiple follicles—requires careful stimulation protocols
• "Coasting" (withholding final trigger until oestradiol plateaus) reduces OHSS risk
• GnRH antagonist protocols with GnRH agonist trigger reduce OHSS risk
• Elective embryo freezing (freeze-all strategy) may be recommended to avoid OHSS in fresh cycle

5. Metabolic Management

Metformin (Insulin Sensitiser)

Indications in PCOS:

1. Impaired fasting glucose or impaired glucose tolerance (diabetes prevention)
2. Type 2 diabetes mellitus
3. Adjunct to ovulation induction (as above)
4. Some use for metabolic improvement even without IGT (controversial)

Evidence:

• Diabetes Prevention Program: Metformin reduced progression from IGT to diabetes by 31% in high-risk individuals [26]
• Improves insulin sensitivity, reduces androgen levels, may improve menstrual regularity
• Limited evidence for weight loss (modest effect, 1-2kg average)

Dose: 500-850mg two to three times daily, or extended-release formulation

Monitoring: Baseline and annual renal function (eGFR); contraindicated if eGFR less than 30 mL/min

Note: Not licensed for PCOS in many countries (UK: off-label use); primarily indicated for diabetes/pre-diabetes

Lipid Management

• Lifestyle modification: First-line for all
• Statin Therapy: If LDL > 5 mmol/L, or 10-year cardiovascular risk > 10% (using QRISK or similar)
• Monitoring: Fasting lipid profile at diagnosis, then every 2-5 years depending on results and other risk factors

Blood Pressure Management

• Screen at baseline and annually
• Treat hypertension (target less than 140/90, or less than 130/80 if diabetes/high CVD risk)
• Weight loss, exercise, and dietary sodium reduction
• Pharmacotherapy: ACE inhibitors or angiotensin receptor blockers (ARBs) preferred (additional benefit on insulin sensitivity); avoid in women attempting pregnancy

6. Psychological Support

• Screen for depression and anxiety using validated tools (PHQ-9, GAD-7)
• Referral to psychologist or counselling services as appropriate
• Cognitive behavioural therapy effective for body image concerns
• Consider impact of hirsutism on quality of life—aggressive cosmetic and medical management
• Peer support groups may be beneficial

Special Populations

Adolescents

• PCOS diagnosis controversial in adolescence (irregular cycles physiological for 2 years post-menarche)
• Avoid over-diagnosis; ultrasound criteria should NOT be used in adolescents
• Management: Lifestyle modification, COCP for menstrual regulation
• Avoid labelling unless clear hyperandrogenism and persistent oligo-anovulation

Pregnancy

• Increased risk: Gestational diabetes (screen with OGTT at 24-28 weeks), pregnancy-induced hypertension, pre-eclampsia, preterm delivery
• Metformin in pregnancy: Emerging evidence may reduce gestational diabetes and pregnancy loss, but not standard practice—individualised decision
• COCP, spironolactone, finasteride: STOP before conception (teratogenic/contraindicated)

Post-Menopause

• Reproductive symptoms (oligo-anovulation, infertility) resolve
• Metabolic risk persists and may worsen: continue diabetes screening, cardiovascular risk management
• Consider HRT for menopausal symptoms (no specific contraindications in PCOS)

---

8. Complications

---

9. Prognosis and Long-Term Outcomes

Natural History

Reproductive Years:

• Chronic condition with fluctuating symptoms
• Severity influenced by weight changes, lifestyle, and age
• Spontaneous ovulation may occur intermittently
• Fertility potential preserved but often delayed without intervention

Peri-Menopause and Beyond:

• Reproductive symptoms (oligo-anovulation, infertility) resolve
• Hyperandrogenism may improve (hirsutism may stabilise or slowly regress)
• Metabolic features persist: diabetes risk, cardiovascular risk remain elevated lifelong
• Endometrial cancer risk remains elevated in post-menopausal women with history of chronic anovulation

Impact of Weight Loss

Weight reduction of 5-10% in overweight/obese women produces:

• 50-60% restoration of ovulation
• Significant improvement in insulin sensitivity
• Reduction in androgens and SHBG normalisation
• Improvement in metabolic parameters (lipids, glucose, blood pressure)
• Reduced diabetes and cardiovascular risk

Weight loss is the single most effective intervention with greatest long-term health benefits.

Impact of Treatment

• COCP: Effective symptom control (menstrual regulation, hirsutism, acne) but does not alter underlying metabolic pathophysiology; benefits cease when discontinued
• Metformin: May reduce progression to diabetes in women with IGT; modest metabolic benefits
• Ovulation Induction: High success rates for achieving pregnancy in motivated women
• Lifestyle Modification: Only intervention proven to modify long-term metabolic trajectory

Long-Term Monitoring

All women with PCOS require lifelong monitoring:

---

10. Prevention and Screening

Primary Prevention

No established strategies to prevent PCOS in genetically predisposed individuals. However, prevention of obesity in childhood and adolescence may reduce phenotypic severity and delay metabolic complications.

Secondary Prevention (Preventing Complications)

1. Diabetes Prevention:

   • Lifestyle modification (diet, exercise, weight loss)
   • Metformin for women with impaired glucose tolerance
   • Regular screening with OGTT

2. Endometrial Cancer Prevention:

   • Regular withdrawal bleeds (minimum every 3-4 months)
   • COCP or cyclical progestogen
   • Endometrial assessment (ultrasound ± biopsy) if amenorrhoea > 1 year

3. Cardiovascular Disease Prevention:

   • Aggressive management of modifiable risk factors (obesity, hypertension, dyslipidaemia, smoking)
   • Statin and antihypertensive therapy when indicated
   • Lifestyle modification

Screening Recommendations

For Women with PCOS:

• Glucose tolerance testing at diagnosis, then every 2-3 years (annually if IGT)
• Lipid profile at diagnosis, then every 2-5 years
• Blood pressure annually
• Screen for depression/anxiety

For First-Degree Relatives:

• No formal screening protocols, but consider assessment if symptoms (oligomenorrhoea, hirsutism) develop
• Higher genetic risk warrants proactive lifestyle counselling

---

11. Key Guidelines

International Evidence-Based Guideline (2018)

Organisation: European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM) [2]

Key Recommendations:

1. Diagnosis: Rotterdam criteria (2 of 3: oligo-anovulation, hyperandrogenism, polycystic ovaries)
2. Lifestyle: First-line for all overweight/obese women; 5-10% weight loss target
3. Fertility: Letrozole first-line for ovulation induction (superior to clomiphene)
4. Metabolic Screening: OGTT at diagnosis and every 2-3 years; screen for NAFLD, OSA, cardiovascular risk
5. Menstrual Regulation: COCP or cyclical progestogen for endometrial protection
6. Hirsutism: COCP first-line; anti-androgens (spironolactone) as second-line or adjunct
7. Psychological: Screen for anxiety, depression, eating disorders, body image concerns

RCOG Green-top Guideline No. 33 (2014)

Title: Long-term Consequences of Polycystic Ovary Syndrome

Key Recommendations:

• All women with PCOS should be counselled about long-term health risks (diabetes, cardiovascular disease, endometrial cancer)
• Regular metabolic screening essential
• Weight management is cornerstone of long-term health
• Endometrial protection mandatory in women with oligo/amenorrhoea

NICE Clinical Guideline (Fertility, 2013)

Recommendations for PCOS-related Infertility:

• Offer lifestyle advice to all overweight women with PCOS (BMI > 25)
• Offer metformin to women with BMI > 25 in combination with clomiphene (note: Letrozole evidence post-dates this guideline)
• Consider laparoscopic ovarian drilling if resistant to medical ovulation induction

---

12. Examination Focus

Common MRCOG/MRCP Exam Questions

1. "What are the Rotterdam criteria for diagnosing PCOS?"

   • Answer: 2 of 3 required: (1) Oligo-ovulation or anovulation, (2) Clinical or biochemical hyperandrogenism, (3) Polycystic ovaries on ultrasound (≥20 follicles 2-9mm or ovarian volume > 10mL). Must exclude other causes.

2. "What is the first-line medical treatment for ovulation induction in PCOS?"

   • Answer: Letrozole (aromatase inhibitor) is now first-line based on PPCOS II trial showing superior live birth rates vs clomiphene. Dose 2.5-7.5mg days 3-7 of cycle.

3. "A 28-year-old woman with PCOS has amenorrhoea for 18 months. What is your management?"

   • Answer: Endometrial protection is urgent priority. Perform transvaginal ultrasound to assess endometrial thickness. If > 10-12mm, consider endometrial biopsy to exclude hyperplasia/malignancy. Initiate regular withdrawal bleeds with COCP or cyclical progestogen (minimum every 3 months).

4. "What metabolic complications are associated with PCOS?"

   • Answer: Type 2 diabetes (4-fold increased risk), metabolic syndrome (prevalence 33-47%), cardiovascular disease (2-fold increased risk), non-alcoholic fatty liver disease (prevalence 40-50%), dyslipidaemia, hypertension.

5. "What are the red flag features that suggest a diagnosis other than PCOS?"

   • Answer: (1) Virilisation (deep voice, clitoromegaly, balding), (2) Testosterone > 5 nmol/L, (3) Rapid onset symptoms, (4) Cushingoid features, (5) Galactorrhoea (suggests prolactinoma). These require urgent investigation for androgen-secreting tumour or other endocrinopathy.

Viva Points

Opening Statement: "Polycystic Ovarian Syndrome is the most common endocrine disorder affecting women of reproductive age, with a prevalence of approximately 10-13%. It is a heterogeneous condition characterised by reproductive, metabolic, and psychological features. Diagnosis is based on the Rotterdam criteria, requiring 2 of 3: oligo-anovulation, hyperandrogenism, and polycystic ovarian morphology. Importantly, PCOS carries significant long-term health implications including a 4-fold increased risk of type 2 diabetes and 3-fold increased risk of endometrial cancer, necessitating lifelong monitoring and metabolic risk management."

Key Facts to Mention:

• PPCOS II Trial (NEJM 2014): Letrozole superior to clomiphene for live birth (27.5% vs 19.1%)
• Insulin resistance present in 70% of obese PCOS, 30-40% of lean PCOS
• Weight loss of 5-10% restores ovulation in 50-60% of women
• Rotterdam criteria (2003) most widely used diagnostic standard
• ESHRE/ASRM 2018 international guideline recommends letrozole first-line for ovulation induction

Model Answer for Management Question: "My approach to managing this woman with PCOS would be holistic and individualised. First, I would assess her primary concerns—whether fertility, menstrual irregularity, hirsutism, or metabolic health. If she is overweight (BMI > 25), lifestyle modification targeting 5-10% weight loss would be foundational, as this can restore ovulation in over 50% of women. For menstrual regulation and endometrial protection, I would offer combined oral contraceptive pill or cyclical progestogen to ensure withdrawal bleeds at least every 3 months. If fertility is desired, I would recommend letrozole as first-line ovulation induction based on the PPCOS II trial evidence. For hirsutism, COCP is first-line, with consideration of anti-androgens such as spironolactone as adjunct. Crucially, I would perform metabolic screening with oral glucose tolerance test, lipid profile, and blood pressure, and counsel her about long-term diabetes and cardiovascular risk, arranging ongoing monitoring as per ESHRE guidelines."

Common Mistakes

❌ Diagnosing PCOS based on ultrasound alone: Polycystic ovarian morphology is common (20-30% of women) and does not equal PCOS without associated clinical features

❌ Missing the need for endometrial protection: Failing to induce withdrawal bleeds in women with prolonged amenorrhoea significantly increases endometrial cancer risk

❌ Using LH:FSH ratio as diagnostic requirement: This ratio is suggestive but neither sensitive nor specific; not required for diagnosis

❌ Not screening for diabetes: OGTT is essential at diagnosis and every 2-3 years thereafter

❌ Prescribing spironolactone or finasteride without contraception: These are teratogenic; reliable contraception is mandatory

❌ Starting clomiphene as first-line for fertility: Letrozole is now first-line based on superior evidence

❌ Over-diagnosing PCOS in adolescents: Irregular cycles are physiological for 2 years post-menarche; diagnosis should be cautious

---

13. Patient and Layperson Explanation

What is PCOS?

Polycystic Ovarian Syndrome (PCOS) is a common hormonal condition affecting about 1 in 10 women. It means your ovaries and hormones work slightly differently than usual. Your body may produce a bit more of a hormone called testosterone (which men have more of), and this can affect your periods, fertility, and appearance.

What causes it?

We don't know exactly why some women develop PCOS. It seems to run in families (if your mum or sister has it, you're more likely to), and it's linked to how your body handles a hormone called insulin (which controls blood sugar). Many women with PCOS have "insulin resistance," meaning their body needs more insulin to control blood sugar, and this extra insulin can affect the ovaries.

What are the "cysts"?

Despite the name, the "cysts" aren't really cysts. They're actually small, immature egg follicles that started to grow but got stuck and didn't develop fully. This happens because the hormone balance isn't quite right. These follicles are harmless and don't need surgery—they're just a sign that ovulation (egg release) isn't happening regularly.

What are the symptoms?

• Irregular or absent periods: Because you're not releasing an egg every month
• Difficulty getting pregnant: But many women with PCOS do conceive, often with simple treatments
• Excess hair growth (face, chest, stomach): Due to higher testosterone levels
• Acne and oily skin
• Weight gain, particularly around the tummy
• Thinning hair on your head

Does it mean I can't have children?

No. PCOS can make it harder to conceive naturally because you may not be releasing an egg every month, but it doesn't mean you can't have children. Many women with PCOS get pregnant naturally, and for those who need help, simple tablet medications (like letrozole) are very effective at stimulating ovulation. PCOS does NOT mean you are infertile.

Why does my weight matter?

Fat tissue affects your hormones. Carrying extra weight makes insulin resistance worse, which makes your ovaries produce even more testosterone, creating a vicious cycle. The good news: losing just 5-10% of your weight (e.g., 5-8kg if you weigh 80kg) can restart your periods and improve fertility, often without needing medication. Weight loss is the single most powerful treatment.

What are the long-term health risks?

Women with PCOS have a higher risk of developing type 2 diabetes and heart disease later in life because of the insulin resistance. There's also a slightly increased risk of cancer of the womb lining (endometrium) if you don't have regular periods, because the lining builds up without being shed. This is why regular check-ups and managing your weight are so important.

How is it treated?

Treatment depends on your main concerns:

• If you want regular periods: The contraceptive pill or other hormones can regulate your cycle and protect the womb lining
• If you want to get pregnant: Medications like letrozole can help you ovulate
• If excess hair/acne bothers you: The contraceptive pill, creams, and hair removal treatments can help
• For long-term health: Healthy eating, exercise, and weight loss (if overweight) are the most important

Can it be cured?

PCOS is a lifelong condition, but symptoms can be very well controlled. Many women find their symptoms improve with weight loss and treatment. After menopause, period problems and fertility concerns obviously resolve, but it's still important to maintain a healthy lifestyle for your metabolic health.

What should I do?

• See your doctor for proper diagnosis and screening for diabetes and other health risks
• Focus on a healthy lifestyle—this truly makes the biggest difference
• If you want to get pregnant, seek advice early so you can access effective treatments
• Don't suffer in silence with unwanted hair or acne—treatments are available
• Remember: PCOS is very common, and most women manage it very well

---

14. References

Primary Sources

1. Bozdag G, Mumusoglu S, Zengin D, Karabulut E, Yildiz BO. The prevalence and phenotypic features of polycystic ovary syndrome: a systematic review and meta-analysis. Hum Reprod. 2016;31(12):2841-2855. doi:10.1093/humrep/dew218

2. Teede HJ, Misso ML, Costello MF, et al. Recommendations from the international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Hum Reprod. 2018;33(9):1602-1618. doi:10.1093/humrep/dey256

3. Dunaif A. Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis. Endocr Rev. 1997;18(6):774-800. doi:10.1210/edrv.18.6.0318

4. Moran LJ, Misso ML, Wild RA, Norman RJ. Impaired glucose tolerance, type 2 diabetes and metabolic syndrome in polycystic ovary syndrome: a systematic review and meta-analysis. Hum Reprod Update. 2010;16(4):347-363. doi:10.1093/humupd/dmq001

5. Barry JA, Azizia MM, Hardiman PJ. Risk of endometrial, ovarian and breast cancer in women with polycystic ovary syndrome: a systematic review and meta-analysis. Hum Reprod Update. 2014;20(5):748-758. doi:10.1093/humupd/dmu012

6. Balen AH, Conway GS, Kaltsas G, et al. Polycystic ovary syndrome: the spectrum of the disorder in 1741 patients. Hum Reprod. 1995;10(8):2107-2111. doi:10.1093/oxfordjournals.humrep.a136243

7. Azziz R, Carmina E, Dewailly D, et al. Positions statement: criteria for defining polycystic ovary syndrome as a predominantly hyperandrogenic syndrome: an Androgen Excess Society guideline. J Clin Endocrinol Metab. 2006;91(11):4237-4245. doi:10.1210/jc.2006-0178

8. Nastri CO, Teixeira DM, Moroni RM, Leitão VM, Martins WP. Ovarian hyperstimulation syndrome: pathophysiology, staging, prediction and prevention. Ultrasound Obstet Gynecol. 2015;45(4):377-393. doi:10.1002/uog.14684

9. Boomsma CM, Eijkemans MJ, Hughes EG, Visser GH, Fauser BC, Macklon NS. A meta-analysis of pregnancy outcomes in women with polycystic ovary syndrome. Hum Reprod Update. 2006;12(6):673-683. doi:10.1093/humupd/dml036

10. Polson DW, Adams J, Wadsworth J, Franks S. Polycystic ovaries—a common finding in normal women. Lancet. 1988;1(8590):870-872. doi:10.1016/s0140-6736(88)91612-1

11. Derksen J, Nagesser SK, Meinders AE, Haak HR, van de Velde CJ. Identification of virilizing adrenal tumors in hirsute women. N Engl J Med. 1994;331(15):968-973. doi:10.1056/NEJM199410133311502

12. Kiddy DS, Hamilton-Fairley D, Bush A, et al. Improvement in endocrine and ovarian function during dietary treatment of obese women with polycystic ovary syndrome. Clin Endocrinol. 1992;36(1):105-111. doi:10.1111/j.1365-2265.1992.tb02909.x

13. Moran C, Tena G, Moran S, Ruiz P, Reyna R, Duque X. Prevalence of polycystic ovary syndrome and related disorders in mexican women. Gynecol Obstet Invest. 2010;69(4):274-280. doi:10.1159/000277640

14. Welt CK, Carmina E. Clinical review: Lifecycle of polycystic ovary syndrome (PCOS): from in utero to menopause. J Clin Endocrinol Metab. 2013;98(12):4629-4638. doi:10.1210/jc.2013-2375

15. Vink JM, Sadrzadeh S, Lambalk CB, Boomsma DI. Heritability of polycystic ovary syndrome in a Dutch twin-family study. J Clin Endocrinol Metab. 2006;91(6):2100-2104. doi:10.1210/jc.2005-1494

16. Blank SK, McCartney CR, Marshall JC. The origins and sequelae of abnormal neuroendocrine function in polycystic ovary syndrome. Hum Reprod Update. 2006;12(4):351-361. doi:10.1093/humupd/dml017

17. Nestler JE, Jakubowicz DJ, de Vargas AF, Brik C, Quintero N, Medina F. Insulin stimulates testosterone biosynthesis by human thecal cells from women with polycystic ovary syndrome by activating its own receptor and using inositolglycan mediators as the signal transduction system. J Clin Endocrinol Metab. 1998;83(6):2001-2005. doi:10.1210/jcem.83.6.4886

18. Poretsky L, Cataldo NA, Rosenwaks Z, Giudice LC. The insulin-related ovarian regulatory system in health and disease. Endocr Rev. 1999;20(4):535-582. doi:10.1210/edrv.20.4.0374

19. González F, Rote NS, Minium J, Kirwan JP. Reactive oxygen species-induced oxidative stress in the development of insulin resistance and hyperandrogenism in polycystic ovary syndrome. J Clin Endocrinol Metab. 2006;91(1):336-340. doi:10.1210/jc.2005-1696

20. Apridonidze T, Essah PA, Iuorno MJ, Nestler JE. Prevalence and characteristics of the metabolic syndrome in women with polycystic ovary syndrome. J Clin Endocrinol Metab. 2005;90(4):1929-1935. doi:10.1210/jc.2004-1045

21. Cooney LG, Lee I, Sammel MD, Dokras A. High prevalence of moderate and severe depressive and anxiety symptoms in polycystic ovary syndrome: a systematic review and meta-analysis. Hum Reprod. 2017;32(5):1075-1091. doi:10.1093/humrep/dex044

22. Moran LJ, Hutchison SK, Norman RJ, Teede HJ. Lifestyle changes in women with polycystic ovary syndrome. Cochrane Database Syst Rev. 2011;(7):CD007506. doi:10.1002/14651858.CD007506.pub3

23. Swiglo BA, Cosma M, Flynn DN, et al. Clinical review: Antiandrogens for the treatment of hirsutism: a systematic review and metaanalyses of randomized controlled trials. J Clin Endocrinol Metab. 2008;93(4):1153-1160. doi:10.1210/jc.2007-2430

24. Legro RS, Brzyski RG, Diamond MP, et al. Letrozole versus clomiphene for infertility in the polycystic ovary syndrome. N Engl J Med. 2014;371(2):119-129. doi:10.1056/NEJMoa1313517

25. Palomba S, Orio F Jr, Falbo A, et al. Prospective parallel randomized, double-blind, double-dummy controlled clinical trial comparing clomiphene citrate and metformin as the first-line treatment for ovulation induction in nonobese anovulatory women with polycystic ovary syndrome. J Clin Endocrinol Metab. 2005;90(7):4068-4074. doi:10.1210/jc.2005-0110

26. Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346(6):393-403. doi:10.1056/NEJMoa012512

---

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists and refer to the most current guidelines.