Objective: To determine the prevalence of polycystic ovaries as identified by ultrasound in a group of young, postmenarcheal women in the normal population, and to investigate how polycystic ovaries are related to the spectrum of clinical and biochemical symptoms associated with the polycystic ovary syndrome (PCOS).
Design: Cross-sectional observational study.
Subjects and methods: Volunteers were recruited from two universities and two general practice surgeries in Oxford. 230 women aged 18-25 years participated. Information collected and measurements performed included: a menstrual history, anthropometric measurements, clinical observation of acne and hirsutism, transabdominal pelvic ultrasound, and biochemical analysis of a fasting blood sample.
Main outcome measures: Prevalence of polycystic ovaries and their association with symptoms of the polycystic ovary syndrome.
Results: Polycystic ovarian morphology was identified in 74 (33%, 95% CI = 27-39%) of the 224 women who attended for an ultrasound scan. In the non-users of hormonal contraception, irregular menstrual cycles were 20% more common in women with polycystic ovaries than in women with normal ovaries (P = 0.07). There were no significant differences in acne, hirsutism, body mass index or body fat percentage between women with polycystic and normal ovaries. Analysis of biochemical data showed that women with polycystic ovaries had higher total serum testosterone concentrations (P = 0.03). The prevalence of PCOS in this age group was as low as 8% or as high as 26% depending on which criteria were applied to define the syndrome. Sub-group analyses of women according to ovarian morphology and features of PCOS revealed greater mean BMI in women with PCOS, and also indicated lower fasting insulin concentrations and greater insulin sensitivity in polycystic ovary and PCOS groups when compared to women with normal ovaries.
Conclusions: Polycystic ovaries are very common in this age group but are not necessarily associated with other symptomatology. The prevalence of polycystic ovary syndrome varies widely according to the definition applied. Sub-group analysis of women with polycystic ovaries according to the presence or absence of features of polycystic ovary syndrome does not reveal an increasing trend for progression of endocrine abnormalities usually associated with polycystic ovary syndrome.