Progestins and thrombosis.

The absolute risk of venous thrombosis and embolism (VTE)--a rare usually mild event--is small. In the general population of reproductive-age women the published annual incidence of VTE ranges around one event per 10000 women. In women taking any combination oral contraceptives (OC) this incidence is increased to 3-4/10000 women annually. According to the most recent official statement of the European Drug Authority it is probable that women taking OCs containing desogestrel or gestodene have a small excess risk (best estimate 1.5- 2.0 increased risk) compared with OCs containing other progestins and the same dose of ethinyl estradiol although the published risk estimates range from 0.8- 4.2. Pregnancy increases the estimated incidence to 6/10000. With the existence of a familial thrombophilia such as factor V Leiden mutation the risk of thrombosis is about 8/10000 in OC nonusers and nearly 30/10000 in OC users. The benefits of OC use in healthy women far outweigh the risks. The benefits and risks of OC use should not be considered in isolation. Medical counseling of women should take into account all aspects of benefit and risk (including pre-existing risk factors) and evaluate these aspects in the context of the individual woman. (authors)