15.7 Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS)

Polycystic Ovary Syndrome (PCOS) is the most prevalent endocrine disorder in reproductive-age individuals, affecting 6% to 15% of females worldwide. It is a heterogeneous, multi-system disorder driven by neuroendocrine dysfunction, hyperandrogenism, and metabolic insulin resistance.

Rotterdam Consensus Diagnostic Criteria

Diagnosis requires the presence of at least two of the following three features, provided other simulating disorders are systematically excluded:

1. Oligo- or Anovulation: Menstrual cycles >35 days apart or <8 cycles per calendar year.
2. Clinical and/or Biochemical Hyperandrogenism:
   • Clinical: Moderate-to-severe inflammatory acne, androgenic alopecia, and hirsutism. Hirsutism is objectively quantified using the modified Ferriman-Gallwey (mFG) score (assessing terminal hair growth in 9 androgen-sensitive body areas; a score ≥8 in White/Black individuals or ≥4 to 6 in Asian individuals defines hirsutism).
   • Biochemical: Elevated total testosterone, free testosterone, or dehydroepiandrosterone sulfate (DHEA-S).
3. Polycystic Ovarian Morphology (PCOM) on Ultrasound:
   • High-resolution transvaginal ultrasound demonstrating ≥20 follicles per ovary measuring 2 to 9 mm in diameter ("string of pearls" sign), OR an increased ovarian volume ≥10 mL in either ovary (excluding dominant follicles >10 mm or corpora lutea).

Mandatory Differential Exclusions

PCOS remains a diagnosis of exclusion. The nurse-midwife must rule out mimic disorders before confirming the diagnosis:

• Non-Classic Congenital Adrenal Hyperplasia (NCAH): Measure early morning fasting 17-hydroxyprogesterone (17-OHP). A level <200 ng/dL reliably excludes 21-hydroxylase deficiency; levels >200 ng/dL warrant an ACTH stimulation test.
• Cushing Syndrome: Screen with 24-hour urinary free cortisol or late-night salivary cortisol if moon facies, purple abdominal striae, buffalo hump, or severe hypertension are present.
• Androgen-Secreting Tumors: Consider if virilization is rapid, abrupt, or severe (clitoromegaly, deepening voice, temporal balding), or total testosterone is markedly elevated (>150–200 ng/dL) or DHEA-S >700–800 mcg/dL. Image ovaries and adrenals.
• Thyroid Disease & Hyperprolactinemia: Exclude via TSH and serum prolactin.

Pathophysiology & Metabolic Sequelae

The core pathophysiology is a vicious metabolic-endocrine loop:

• Hyperinsulinemia & Insulin Resistance: Peripheral insulin resistance in skeletal muscle and adipose tissue leads to compensatory hyperinsulinemia. High insulin acts synergistically with elevated LH pulses to stimulate ovarian theca cell androgen production. Concurrently, hyperinsulinemia suppresses hepatic synthesis of Sex Hormone-Binding Globulin (SHBG), causing a dramatic surge in bioavailable free testosterone.
• Cardiometabolic Consequences: Up to 70% of PCOS patients exhibit insulin resistance; 30% to 40% develop impaired glucose tolerance or overt Type 2 Diabetes Mellitus by age 40. Patients have an elevated incidence of metabolic syndrome, atherogenic dyslipidemia (low HDL, high triglycerides), nonalcoholic fatty liver disease (NAFLD / MASLD), obstructive sleep apnea, and vascular endothelial dysfunction. Screening with a fasting lipid panel and a 75-gram 2-hour Oral Glucose Tolerance Test (OGTT) is recommended every 1 to 3 years.
• Endometrial Cancer Risk: Chronic, unmitigated anovulation deprives the endometrium of cyclic progesterone. Unopposed estrogen promotes unbridled endometrial epithelial proliferation, increasing the relative risk of endometrial adenocarcinoma 3- to 5-fold.

Comprehensive Midwifery Management

PCOS Stepwise Clinical Management
├── Foundational First-Line: Lifestyle Modification (5% - 10% Weight Loss)
│   └── Restores spontaneous ovulation, reduces hyperinsulinemia, increases SHBG
├── Cycle Regulation & Endometrial Protection (Non-Pregnancy Seeking)
│   ├── Combined Oral Contraceptives (COCs - Preferred First-Line)
│   │   └── Ethinyl estradiol suppresses LH & boosts SHBG; progestin protects endometrium
│   ├── 52 mg Levonorgestrel IUD (LNG-IUD) or Cyclic Oral Progestins
│   │   └── Excellent endometrial protection if COCs contraindicated or not tolerated
│   └── Metformin (500–2,000 mg/day)
│       └── Improves insulin sensitivity, reduces progression to T2DM, modest weight benefit
├── Dermatologic / Hyperandrogenism Management
│   ├── COCs with low-androgenic progestin (drospirenone, desogestrel, norgestimate)
│   └── Spironolactone (50–200 mg/day - Antiandrogen)
│       └── CAUTION: Teratogenic to male fetus; MANDATORY reliable contraception!
└── Ovulation Induction for Fertility (Pregnancy Seeking)
    └── Letrozole (Aromatase inhibitor, 2.5–7.5 mg/day on Days 3–7) - First-Line agent

• Lifestyle Intervention: Foundational therapy. A modest 5% to 10% reduction in total body weight significantly reduces visceral adiposity, restores spontaneous ovulatory menses in up to 50% of overweight patients, lowers circulating androgens, and enhances fertility.
• Combined Oral Contraceptive Pills (COCs): First-line medical therapy for individuals not desiring immediate conception. The estrogen component suppresses pituitary LH secretion (reducing ovarian androgen synthesis) and dramatically elevates hepatic SHBG production, binding circulating free androgens. The progestin component induces cyclic endometrial shedding, neutralizing the risk of endometrial hyperplasia. Formulations with low-androgenic or antiandrogenic progestins (drospirenone, norgestimate, or desogestrel) are preferred.
• Endometrial Protection Alternatives: For individuals with contraindications to estrogen (e.g., migraine with aura, hypertension, history of VTE), the 52 mg LNG-IUD delivers potent, continuous local progestin that prevents hyperplasia for up to 8 years. Alternatively, prescribe cyclic oral progestins: Medroxyprogesterone acetate 10 mg PO daily for 12 to 14 days every 1 to 3 months, or oral micronized progesterone 200 mg nightly for 12 to 14 days.
• Metformin: An insulin-sensitizing biguanide (titrated from 500 mg up to 1,500–2,000 mg daily). Indicated for PCOS individuals with impaired glucose tolerance, metabolic syndrome, or prediabetes. It modestly lowers fasting insulin, reduces free testosterone, and can facilitate weight loss.
• Spironolactone: An aldosterone antagonist with potent antiandrogenic activity (blocks androgen receptors and inhibits 5α-reductase). Dosages of 50 to 200 mg daily significantly reduce hirsutism and inflammatory acne over a 6- to 12-month trial.
  • Critical Midwifery Practice Point: Spironolactone can cause feminization of the external genitalia in a developing male fetus. It must always be co-prescribed with highly effective contraception (e.g., COCs, IUD, or implant).
• Ovulation Induction for Fertility: Per the landmark NICHD PPCOS II trial, Letrozole (an aromatase inhibitor, 2.5 to 7.5 mg daily on cycle days 3 to 7) is the first-line pharmacologic agent for ovulation induction in PCOS, demonstrating significantly higher live-birth rates (27.5% vs. 19.1%) and ovulation rates compared to clomiphene citrate, along with a lower incidence of high-order multiple gestations.