ESHRE Guideline
MRCOG Part 2
International Evidence-Based Guideline for the Assessment and Management of Polycystic Ovary Syndrome (PCOS)
Note: NICE published a draft guideline on 1 July 2026 proposing PCOS be renamed "PMOS" (Polyendocrine Metabolic Ovarian Syndrome) in future UK guidance, currently in public consultation until 11 August 2026 with a final guideline expected December 2026. Not yet finalised — this file uses the current internationally-recognised name (PCOS) and will be revisited once NICE's guidance is confirmed.
Diagnostic Criteria
- PCOS affects approximately 1 in 8 women of reproductive age.
- Diagnosis (adults) uses the Rotterdam criteria: 2 of 3 of — (1) oligo/anovulation, (2) clinical or biochemical hyperandrogenism, (3) polycystic ovarian morphology on ultrasound (or elevated AMH as an alternative to ultrasound in adults).
- In adolescents, ultrasound and AMH are not used for diagnosis (ovarian morphology overlaps heavily with normal adolescent ovaries); diagnosis requires both irregular cycles (per adolescent-specific criteria accounting for normal post-menarchal irregularity) AND biochemical or clinical hyperandrogenism.
- Exclude other causes before diagnosing PCOS: thyroid dysfunction, hyperprolactinaemia, non-classic congenital adrenal hyperplasia.
Screening and Associated Risks
- Screen for cardiometabolic risk factors: impaired glucose tolerance/type 2 diabetes (oral glucose tolerance test recommended, particularly with obesity, family history, or high-risk ethnicity), dyslipidaemia, hypertension.
- Psychological screening is explicitly recommended — anxiety and depression are significantly more common in PCOS and are under-recognised; the guideline calls for routine screening, not opportunistic enquiry only.
- Endometrial protection: chronic anovulation raises endometrial hyperplasia/cancer risk — cycle regulation or endometrial surveillance is advised where amenorrhoea is prolonged.
Management
- First-line for all features: lifestyle intervention (diet, exercise, behavioural support) — modest weight loss (5-10%) can restore ovulation and improve metabolic and hyperandrogenic features.
- Menstrual irregularity / endometrial protection: combined hormonal contraception first-line; alternatives include cyclical progestogens or the levonorgestrel intrauterine system.
- Hyperandrogenism (hirsutism/acne): combined hormonal contraception first-line; anti-androgens (e.g. spironolactone) may be added after 6 months of inadequate response, with effective contraception given teratogenicity risk.
- Infertility (anovulatory, no other cause): letrozole is recommended first-line for ovulation induction (superior live-birth rates to clomiphene in PCOS-specific trials); clomiphene citrate (alone or with metformin) and metformin alone are alternatives. Gonadotrophins or laparoscopic ovarian drilling are second-line.
- Metformin has a role in improving metabolic parameters and can be combined with letrozole/clomiphene, but is not first-line for ovulation induction alone.
High-Yield Exam Points
- Rotterdam criteria (2 of 3), and know the adolescent-specific exception (no ultrasound/AMH-based diagnosis in adolescents).
- Letrozole, not clomiphene, is now first-line for ovulation induction in PCOS — a common point of outdated teaching.
- Psychological screening is an explicit, guideline-mandated part of PCOS assessment, not an optional add-on.
- PCOS affects ~1 in 8 women — a commonly tested prevalence figure.
Source: ESHRE (European Society of Human Reproduction and Embryology), co-developed with ASRM and other international societies. Published in *Human Reproduction* (2023), doi.org/10.1093/humrep/dead156 (2023 (current international standard reference — more current and detailed than RCOG GTG 33, which addresses only the long-term consequences of PCOS and is itself archived; see that file))
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