# Polycystic Ovary Syndrome

> NEET-PG OBG notes on polycystic ovary syndrome covering Rotterdam criteria, investigations, ovulation induction and long-term risks with exam points.

- Canonical URL: https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/polycystic-ovary-syndrome
- Exam / course: NEET-PG · Subject: Obstetrics and Gynaecology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Polycystic Ovary Syndrome", PrepElephant, https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/polycystic-ovary-syndrome

## Direct answer

Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder of reproductive-age women marked by oligo-anovulation, hyperandrogenism and polycystic ovarian morphology. Diagnosis follows the Rotterdam criteria — two of the three features once mimics are excluded. Management is lifestyle-first, with letrozole as first-line ovulation induction for infertility, combined hormonal contraception for cycle control, and metformin for metabolic abnormalities.

## What you must remember

- Rotterdam criteria (two of three) — oligo- or anovulation, clinical (hirsutism, acne, alopecia) or biochemical hyperandrogenism, and polycystic ovarian morphology; the updated international guideline defines this morphology as 20 or more small follicles (2-9 mm) per ovary and/or an ovarian volume of 10 mL or more, replacing the older 12-follicle cut-off.
- Exclude mimics first — hypothyroidism, hyperprolactinaemia, non-classic congenital adrenal hyperplasia (17-OHP), Cushing's syndrome and androgen-secreting tumours.
- Supportive findings — an LH to FSH ratio above 2, insulin resistance, acanthosis nigricans and obesity; lean PCOS also exists, so weight is not a criterion.
- PCOS is the commonest cause of anovulatory infertility; long-term risks include type 2 diabetes, metabolic syndrome, endometrial hyperplasia from chronic unopposed oestrogen, and mood disorders.
- Lifestyle modification leads management — losing around 5 per cent of body weight commonly restores spontaneous ovulation in overweight women.
- Letrozole is the first-line ovulation induction agent, with better live-birth rates than clomiphene in the international guideline; metformin serves mainly metabolic indications, and laparoscopic ovarian drilling is an option in selected women.
- Combined oral contraceptives or cyclical progestogens regulate cycles, treat hirsutism and protect the endometrium; anti-androgens such as spironolactone may be added with reliable contraception.

## Common confusion

Polycystic ovaries on ultrasound are not the same as the syndrome. Many women have multifollicular or polycystic-appearing ovaries without hyperandrogenism or anovulation, and the ultrasound finding alone never makes the diagnosis. Criteria sets also differ — Rotterdam needs two of three features, while the AE-PCOS Society insists hyperandrogenism be present — a favourite distinction in theory exams.

## Exam-focused takeaway

Know the Rotterdam two-of-three rule with the updated 20-follicle ultrasound threshold, the exclusion panel for mimics, and letrozole as the current first-line ovulation induction agent — older textbooks that answer clomiphene are out of date. The 5-per-cent weight-loss figure, the LH to FSH ratio as supportive rather than diagnostic, and endometrial protection strategies round off the stems.

## Frequently asked questions

### What are the Rotterdam criteria for PCOS?

Two of three — oligo or absent ovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound — after excluding other causes.

### Which conditions must be excluded before diagnosing PCOS?

Hypothyroidism, hyperprolactinaemia, non-classic congenital adrenal hyperplasia, Cushing's syndrome and androgen-secreting tumours, using TSH, prolactin, 17-OHP and androgens as indicated.

### What is the first-line treatment for infertility in PCOS?

Letrozole for ovulation induction, preceded by lifestyle modification. It achieves higher live-birth rates than clomiphene and is the guideline-recommended first line.

### Why is metformin used in PCOS?

Chiefly for insulin resistance, impaired glucose tolerance and metabolic benefits, and it may modestly improve cycle regularity. It is not the primary fertility drug.

### What are the long-term health risks of PCOS?

Type 2 diabetes, metabolic syndrome, endometrial hyperplasia and carcinoma from chronic anovulation, and higher cardiovascular risk factors — warranting lifelong follow-up.