Hormonal contraception and venous thromboembolic risk in midlife women.

Several new observational studies have assessed the risk of enous and arterial thrombosis in users of different types of horonal contraception [1–5]. The new studies have confirmed that ombined hormonal products have much more influence on venous hrombosis than they have on the arterial end points, thrombotic troke and myocardial infarction. Thus, among users of combined ral contraceptives (COC) the risk of venous thrombosis is increased –6 times compared to non-users [1–3], while the risk of arterial hrombosis is increased 1.5–2 times [5]. With the withdrawal of 50 g oestrogen COC from the market, he difference in thrombotic risk between middle and lowestrogen COC is of less importance than the influence from ifferent progestogen types. The 2nd generation COC with the rogestogens levonorgestrel and norgestimate confer a three imes increased risk of venous thrombosis, while COC with 3rd desogestrel and gestodene) and 4th (drospirenone) generation rogestogens increase the risk at least six times [1–3]. While the risk of venous thrombosis is highest during the first ear of use, no trend according to length of use has been found for rterial thrombosis. After the first year of use, the risk of venous hrombosis is almost constant. It is now confirmed in several independent studies that the ransdermal contraceptive patch (EVRA) confers more than the ouble risk of venous thrombosis as compared to the correspondng 2nd generation combined pill with norgestimate [4], and at the ame time also increases the risk of arterial thrombosis about three imes [5]. The contraceptive vaginal ring (NuvaRing) increases the isk of venous thrombosis as much as 3rd and 4th generation COC, nd the risk of arterial thrombosis about 21⁄2 times. At the time in eproductive age where the incidence rates of venous and arteial thrombosis are highest, these two non-oral combined products hould therefore generally be avoided. On the other hand, progestogen only contraception including rogestogen only pills with norethisterone or levonorgestrel, levnorgestrel releasing intrauterine system (LNG-IUS), subcutaneous mplant (Implanon) or the oestrogen free pill with desogestrel, all