Objective: To determine whether there is an increased risk of venous thromboembolism (VTE) with anti-androgen oral contraceptives containing cyproterone acetate and ethinyloestradiol.
Methods: Comparison of the frequency of specific oral contraceptive use in patients aged 15 to 55 years discharged from hospital with radiologically confirmed deep vein thrombosis (DVT) and/or pulmonary embolism (PE) with the expected frequency of use derived from national prescription data.
Main outcome measure: Ratio of observed frequency of specific oral contraceptive use in patients with VTE versus expected frequency of use.
Results: The rank order for observed versus expected use was anti-androgen > third-generation, > second-generation, > progestogen-only oral contraceptive agents with ratios of 1.93, 1.36, 0.70, and 0.39, respectively.
Conclusion: The risk of VTE resulting in hospital admission associated with anti-androgen oral contraceptive use is at least as high as with third generation use.