Abstract

Background: Polycystic Ovary Syndrome (PCOS) is tightly associated with insulin resistance and obesity and characterized by hyperandrogenism, chronic oligo-anovulation and polycystic ovarian morphology when fully expressed. The 2003 Rotterdam consensus proposed that two or three of these features were necessary to make the diagnosis, which generated four phenotypes. Several studies have suggested that these phenotypes could differ in their metabolic and endocrine characteristics and that they could vary in the same patient when analyzed throughout life. Aim: To determine if the initial classification of PCOS phenotypes is modified by different physiological conditions. Material and Methods: We performed a non-concurrent prospective analysis of 88 women with PCOS according to the Rotterdam criteria. The effect of physiological conditions such as changes in body weight, pregnancy and ageing more than five years on PCOS phenotype expression was analyzed. Results: Twenty four percent of women became pregnant, 37% decreased and 24% increased their body weight during follow up. These conditions modified significantly the proportion of the different phenotypes (chi(2) = 32.2, p < 0.001). For instance, weight reduction was associated with a change to a better phenotype (p = 0.047) and even a normalization of the PCOS condition in 27% of the patients. On the other hand, an increase in body weight modifying body mass index in one unit, conferred an 8% probability of changing to a worst phenotype. Conclusions: Pregnancy and changes in body weight significantly modify PCOS phenotypes.