Risk of venous thromboembolism with cyproterone or levonorgestrel contraceptives

Results of studies have shown that there is an excess risk of venous thromb oembolism in users of oral contraceptives containing cyproterone compared w ith those containing levonorgestrel. We did a case-control study, in which we assessed the risk of idiopathic venous thromboembolism in women taking c ombined low-dose oestrogen oral contraceptives containing cyproterone (n=24 401) or levonorgestrel (n=75 000). We compared the 26 women in this popula tion who had idiopathic venous thromboembolism with 144 matched controls. 1 2 individuals and 30 controls were taking contraceptives that contained cyp roterone. Our results suggest that risk of venous thromboembolism is increa sed four-fold in women taking contraceptives containing cyproterone by comp arison with those exposed to levonorgestrel.