RESUMO
INTRODUCTION: There is currently neither a clinically useful, reliable and inexpensive assay to measure circulating levels of free testosterone (T) in the range observed in women, nor is there agreement on the serum free T threshold defining hypoandrogenism that is associated with female-impaired sexual function. AIM: Following the Clinical and Laboratory Standards Institute guidelines, we generated clinically applicable ranges for circulating androgens during specific phases of the menstrual cycle in a convenience sample of 120 reproductive-aged, regularly cycling healthy European Caucasian women with self-reported normal sexual function. METHODS: All participants were asked to complete a semistructured interview and fill out a set of validated questionnaires, including the Female Sexual Function Index, the Female Sexual Distress Scale, and the 21-item Beck's Inventory for Depression. Between 8 am and 10 am, a venous blood sample was drawn from each participant during the midfollicular (day 5 to 8), the ovulatory (day 13 to 15), and the midluteal phase (day 19 to 22) of the same menstrual cycle. MAIN OUTCOME MEASURES: Serum levels of total and free testosterone, Delta(4)-androstenedione, dehydroepiandrosterone sulphate and sex hormone-binding globulin during the midfollicular, ovulatory and midluteal phase of the same menstrual cycle. RESULTS: Total and free T levels showed significant fluctuations, peaking during the ovulatory phase. No significant variation during the menstrual cycle were observed for Delta(4)-androstenedione and dehydroepiandrosterone sulphate. Despite the careful selection of participants that yielded an homogeneous group of women without sexual disorders, we observed a wide range of distribution for each of the circulating androgens measured in this study. CONCLUSIONS: This report provides clinically applicable ranges for androgens throughout the menstrual cycle in reproductive-aged, regularly cycling, young healthy Caucasian European women with self-reported normal sexual function.