tokens: BACKGROUND : Cyproterone acetate combined with ethinyl estradiol ( CPA / EE ) is licensed in the UK for the treatment of women with acne and hirsutism and is also a treatment option for polycystic ovary syndrome ( PCOS ). Previous studies have demonstrated an increased risk of venous thromboembolism ( VTE ) associated with CPA / EE compared with conventional combined oral contraceptives ( COCs ). We believe the results of those studies may have been affected by residual confounding .