PMOS / PCOS Phenotypes (Rotterdam A through D)
PMOS / PCOS phenotypes are the four subtypes of polyendocrine metabolic ovarian syndrome (PMOS), formerly polycystic ovary syndrome (PCOS). The four phenotypes follow from the diagnostic criteria set by the 2003 Rotterdam consensus. Each phenotype is a different mix of three features used for diagnosis.
The three features are androgen excess (hyperandrogenism), ovulatory dysfunction, and a polycystic appearance of the ovaries on ultrasound (PCOM). Androgens are hormones such as testosterone. High levels can appear as physical signs or on blood tests.
A diagnosis of PMOS / PCOS requires any two of the three features. This two-of-three rule produces four possible combinations, or phenotypes.12
Type A has all three features. It shows the most hormone and metabolic disruption. It has the highest rates of insulin resistance and androgen excess.
Type B has androgen excess and ovulatory dysfunction, but not polycystic ovaries. Its metabolic risk is close to that of Type A.
Type C has androgen excess and polycystic ovaries, but ovulation still occurs. Its metabolic risk is milder.
Type D has ovulatory dysfunction and polycystic ovaries only, with no androgen excess. It carries the lowest metabolic risk of the four.2
The phenotype changes what a clinician checks first. Types A and B carry the heaviest metabolic burden. A full metabolic workup therefore belongs early, regardless of how the diagnosis was made.
Type C has androgen excess with normal ovulation. Metabolic screening still has a place here. Androgen excess itself carries metabolic risk.
Type D carries the lowest risk of the four. This lower risk shifts the focus to the ovulatory dysfunction itself.
When every case receives the same treatment, without phenotyping, women spend years in care without a real resolution.
PMOS and PCOS name the same condition. The phenotype is where the two labels do the most clinical work.
Two of the three Rotterdam criteria confirm PMOS / PCOS. The specific pair determines the metabolic risk the workup must cover.
Cited in this entry
- Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome (PCOS). https://pubmed.ncbi.nlm.nih.gov/14688154/
- Polycystic Ovarian Syndrome. https://www.ncbi.nlm.nih.gov/books/NBK459251/
This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.
