Oestroprogestative oral contraceptives vary depending on the progestative combined with ethinylestradiol: levonorgestrel, norethisterone or norgestrel in standard contraceptives; desogestrel, gestodene or norgestimate in the so-called third-generation contraceptives; or chlormadinone, cyproterone or drospirenone.

The risk of deep vein thrombosis (DVT) is higher with oestroprogestative contraceptives. It varies according to individual risk factors (personal or family history of DVT, obesity, some blood disorders, etc.), the duration of use, and the dosage of combined ethinylestradiol and progestatives.

In women not using the contraceptive pill, the risk of DVT is estimated at between 5 and 10 cases per 100,000 women treated over one year. It is around 20 for women taking an oral contraceptive combining levonorgestrel or norethisterone with less than 50 mg of ethinylestradiol, and rises to around 30 to 40 with gestodene or desogestrel and 80 cases with cyproterone; it is higher with drospirenone compared with levonorgestrel.

These figures confirm that when it comes to oestroprogestative oral contraception, the combinations ethinylestradiol + levonorgestrel and ethinylestradiol + norethisterone offer the best risk-benefit balance.

©Prescrire February 2011

"Drospirenone: high risk of venous thrombosis"  Prescrire Int 2011 ; 20  (113): 43-44 (Pdf, subscribers only)