Clinical overview
Hyperandrogenism is a state of androgen excess in a woman, expressed clinically (hirsutism, acne, androgenic alopecia, and at the severe end virilisation) and/or biochemically (raised serum androgens). It is one of the most common reproductive-endocrine presentations to gynaecology, and the overwhelming majority of cases — around 70–80% — are accounted for by PMOS (polyendocrine metabolic ovarian syndrome — the condition renamed in 2026 from polycystic ovary syndrome, PCOS). The clinician's job is twofold: first, to recognise the small but critical minority in whom androgen excess signals something dangerous — an androgen-secreting ovarian or adrenal tumour, Cushing's syndrome, or non-classical congenital adrenal hyperplasia — and second, to manage the common, benign causes well, because they carry real consequences for fertility, metabolic health, endometrial protection, and quality of life.
A note on naming. Throughout this chapter the condition is called PMOS, with (formerly PCOS) flagged at first use in each major section. The two terms mean the same disease. FCOG(SA) and MRCOG examinations still use "PCOS" during the transition period (see the dedicated section below), so you must recognise and answer to both.
The single most useful discriminator at the bedside is the tempo. Hirsutism that has crept on slowly over years, around puberty, with menstrual irregularity is the picture of PMOS. Hirsutism that appears suddenly and progresses rapidly, especially with frank virilisation (clitoromegaly, voice deepening, male-pattern temporal balding, increased muscle bulk), is a tumour until proven otherwise and demands urgent investigation. This chapter explains the androgen physiology and the pathophysiology of the major causes, then sets out a safe assessment and management approach. It connects to Contraceptive modalities (the mainstay of medical treatment), Climacteric and menopause (postmenopausal hyperandrogenism), and Heavy menstrual bleeding pathology (anovulatory bleeding and endometrial risk).
From PCOS to PMOS — the 2026 rename
Figure B2.1 — The 2026 rename of PCOS to PMOS (polyendocrine metabolic ovarian syndrome): the same condition, why the name changed, and the global consensus process behind it.
In May 2026 the condition long known as polycystic ovary syndrome (PCOS) was formally renamed polyendocrine metabolic ovarian syndrome (PMOS) through a global consensus published in The Lancet (Teede et al.). The process was deliberately broad — a modified Delphi with nominal-group workshops gathering 14,360 patient and clinician voices across 56 organisations in 195 countries. It is essential to understand that this is the same condition — no diagnostic criteria changed at the rename; only the name did. Three problems with the old name drove the change:
- The "cysts" were always a misnomer. The ovaries in this condition do not contain pathological cysts. What ultrasound shows is a ring of arrested early-antral follicles (the "string of pearls"), 2–9 mm, whose development has stalled — not fluid-filled cysts. The burden of true ovarian cysts is not increased in the condition (Piltonen et al., JAMA Internal Medicine 2026). Naming a disease after a lesion it does not have bred confusion for patients and clinicians alike.
- It is not an ovary-only disease. PMOS is a multisystem polyendocrine and metabolic disorder: insulin resistance affects roughly 85% of patients (and ~75% even of lean patients), with raised lifetime risks of type 2 diabetes, MASLD (metabolic dysfunction–associated steatotic liver disease), dyslipidaemia and cardiovascular disease, alongside the neuroendocrine and psychological burden (depression, anxiety). The new prefixes name what the disease actually is — polyendocrine (neuroendocrine, androgen, insulin and AMH dysregulation), metabolic, and ovarian (retained, deliberately preserving acronym continuity).
- The old name drove stigma and delay. Around 70% of affected women remain undiagnosed and the average delay from first symptom to diagnosis is about 8 years; an ovary-centric, cyst-implying label contributed to both, and sat awkwardly with ICD and research nomenclature.
Transition and the exam. A 3-year transition is under way; the ICD codes and the International Guideline update land in 2028. Until then — and this is the practical point for candidates — FCOG(SA) and MRCOG questions, and most current textbooks and guidelines, still say "PCOS." Lead with PMOS, state "formerly PCOS" on first mention, and treat any exam stem that says "PCOS" as identical to PMOS.