The use of hormone containing contraceptivas gives an increased risk of thromboembolic events, both arterial and venous. In this study we have considered if the different types of contraceptive preparations, which differ in hormoneamount and type of progestin, also differ in the amount in which they increase the risk for thromboembolic events.
The population in this study is the number of women in Norway who used hormone containing contraceptiva from 01.01.1999 to 31.12.2007. This number has been set equal to the number of sold doses pr. day (DDD/d) for the same period of time. The included contraceptivas are all the preparations in ATC-group G03A and the ATC-group G03HB01. The side effects that have been included are the ones with thromboembolic diagnoses. From these numbers of sold preparations and reported thromboembolic events we have estimated a risk ratio for a venous or an arterial thromboembolic event when using each of the preparations, and then we have compared the risk ratios for each of the preparations by estimating a rate ratio.
Results / Conclusions:
The use of contraceptive preparations that only contain progestin shows a lower risk of both venous and arterial thromboembolic events, compared to the use of combined orale contraceptivas. For both the venous and arterial thromboembolic events the 2.generation preparations, containing estradiol and levonorgestrel, show the lowest risk of the combinationpills. The use of 2.generation pills is seen with a lower risk of thromboembolic events than the use of 3.generation combinationpills or the combinationpill Yasmin.