PCOS phenotype focus: phenotype D under the magnifying glass

Polycystic ovary syndrome (PCOS) is defined as the combination of polycystic morphology, hyperandrogenism, and ovulatory disruption; this heterogeneity presents a conundrum for the medical community. The Rotterdam criteria have governed the diagnosis of PCOS, separating the patient cohort into four distinct phenotypes. It has been suggested that the lone normoandrogenic phenotype, so-called phenotype D, should not be classified as a PCOS subtype, with phenotypes A, B, and C displaying a hyperandrogenic biochemical and clinical profile thought to be characteristic of PCOS. To understand how to treat phenotype D patients, this review shines a spotlight on the phenotype, gathering various reports of how phenotype D is differentiated from the other PCOS phenotypes.