A 28-year-old woman from Delhi presents to the infertility clinic with a 3-year history of primary infertility. She reports regular menstrual cycles (28–30 days) with normal flow and duration. Physical examination reveals hirsutism on the face and abdomen, acne, and a BMI of 32 kg/m². Pelvic ultrasound shows multiple small follicles (8–10 mm) arranged peripherally in both ovaries with increased ovarian stroma. Serum testosterone is 0.8 ng/mL (normal <0.7 ng/mL), LH:FSH ratio is 3.2:1, and fasting insulin is elevated at 18 mIU/L with normal fasting glucose. What is the most likely diagnosis?

Explanation

## Diagnosis: Polycystic Ovary Syndrome (PCOS) ### Clinical Presentation This patient meets the Rotterdam criteria for PCOS diagnosis: - **Ovulatory dysfunction** (regular cycles but anovulation is common; confirmed by ultrasound findings) - **Hyperandrogenism** (clinical: hirsutism, acne; biochemical: elevated testosterone) - **Polycystic ovarian morphology** (≥12 follicles 2–9 mm per ovary, increased stroma) ### Key Biochemical Findings | Parameter | Finding | Significance | |-----------|---------|---------------| | LH:FSH ratio | 3.2:1 (elevated) | Characteristic of PCOS; normal is ~1:1 | | Testosterone | 0.8 ng/mL (↑) | Mild hyperandrogenism | | Fasting insulin | 18 mIU/L (↑) | Insulin resistance present | | Fasting glucose | Normal | Rules out diabetes | **Key Point:** PCOS is diagnosed when ≥2 of 3 Rotterdam criteria are met: (1) oligo-/anovulation, (2) clinical or biochemical hyperandrogenism, (3) polycystic ovarian morphology on ultrasound. This patient satisfies all three. ### Pathophysiology of Infertility in PCOS 1. **Insulin resistance** → hyperinsulinemia → increased ovarian androgen production 2. **Elevated LH** → abnormal follicle development → arrest at 5–8 mm stage 3. **Anovulation** → absent corpus luteum → no progesterone production 4. **Endometrial dysfunction** → impaired receptivity even if ovulation occurs **High-Yield:** PCOS accounts for ~20–25% of female infertility cases in India. The elevated LH:FSH ratio (>2.5:1 or 3:1) is a hallmark biochemical finding. **Clinical Pearl:** Regular menstrual cycles do NOT exclude PCOS; many patients have oligomenorrhea or amenorrhea, but some maintain regular cycles with anovulation ("ovulatory PCOS"). ### Management Overview - **First-line:** Lifestyle modification (weight loss 5–10%), metformin (reduces insulin resistance) - **Ovulation induction:** Clomiphene citrate (anti-estrogen) or letrozole (aromatase inhibitor) - **If resistant:** Gonadotropins or laparoscopic ovarian drilling [cite:Jeffcoate's Principles of Gynaecology Ch 32]