Objective: The effect of combined oral contraceptives (COCs) on female sexuality has long been a matter of discussion, but placebo-controlled studies are lacking. Thus, the aim of the present study was to investigate if an oestradiol-containing COC influences sexual function. Design: Investigator-initiated, randomised, double-blinded, placebo-controlled clinical trial where 202 healthy women were randomised to a combined oral contraceptive (1.5 mg oestradiol and 2.5 mg nomegestrol acetate) or placebo for three treatment cycles. Methods: Sexual function at baseline and during the last week of the final treatment cycle was evaluated by the McCoy Female Sexuality Questionnaire. Serum and hair testosterone levels were assessed at the same tim...