PCOS according to the Rotterdam consensus criteria: change in prevalence among WHO-II anovulation and association with metabolic factors

Objective The current report aims to compare the prevalence of polycystic ovary syndrome (PCOS) diagnosed according to the new Rotterdam criteria (Rott-PCOS) versus the previous criteria as formulated by the National Institutes of Health (NIH) (NIH-PCOS) in women with normogonadotropic (WHO-II) anovulation and assess the frequency of obesity and related factors determined in these women. Design Cohort study based on large anovulation screening database. Setting Two large tertiary referral centres for reproductive medicine. Population WHO-II normogonadotropic, anovulatory, infertility cases. Methods WHO-II cases were extracted from the screening database and classified according to both the Rotterdam and NIH criteria for PCOS. Within these two classes, the prevalence of obesity, hyperglycaemia and insulin resistance was assessed and compared and their relation to the difference in diagnostic criteria applied was analysed. Main outcome measures Prevalence of diagnosis PCOS in the WHO-II anovulation group. Prevalence of obesity, hyperglycaemia and insulin resistance in the two diagnostic classes. Results The Rott-PCOS group appeared to be more than 1.5 times larger than the group classified as NIH-PCOS (91 versus 55% of the WHO-II cohort). Especially, women with ovarian dysfunction and polycystic ovaries at ultrasound scan, but without hyperandrogenism, were added to the PCOS diagnostic group. The Rott-PCOS exhibited a lower frequency of obesity, hyperglycaemia and insulin resistance compared with the NIH-PCOS group. Obese women in the Rott-PCOS group without androgen excess had a different metabolic profile compared with obese women in the NIH-PCOS group, with lower rates of hyperglycaemia and hyperinsulinism, despite comparable distributions of body weight. Conclusion The present findings indicate that with the new Rotterdam consensus criteria, oligo/anovulatory women with less severe metabolic derangement will be added to the heterogeneous group of women with PCOS.