Polycystic ovary syndrome (PCOS) can be classified into at least two subtypes that appear to reflect underlying biological differences, US researchers say.

Their cluster analysis of 893 women, all of European ancestry and diagnosed with PCOS according to US National Institutes of Health criteria, revealed two phenotypically-distinct clusters which the investigators dubbed ‘reproductive’ and ‘metabolic’.

One in five of the women (21-23%) fell into the reproductive subtype, which was characterised by relatively high levels of luteinising hormone and sex hormone-binding globulin and relatively low BMI and fasting insulin, the authors reported in PLOS Medicine.

Nearly two in five women (37-39%) fell into another cluster, in which levels of fasting glucose, fasting insulin and BMI were high, while levels of luteinising hormone and sex hormone-binding globulin were relatively low.