International Evidence-Based Guideline for the Assessment and Management of Polycystic Ovary Syndrome (PCOS)
Embryology), co-developed with ASRM and other international societies. Published in Human Reproduction (2023), doi.org/10.1093/humrep/dead156 more current and detailed than RCOG GTG 33, which addresses only the long-term consequences of PCOS and is itself archived; see that file)
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 (2023 (current international standard reference —)
Read the original on academic.oup.com
MRCOG AI is an independent educational tool. It is not affiliated with, endorsed by, or connected to the Royal College of Obstetricians and Gynaecologists (RCOG).