Thromb Haemostasis
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of second and third generation oral contraceptives and their respective progestagens on the coagulation system in the absence or presence of the factor V Leiden mutation.
Compared to second generation, the use of third generation oral contraceptives has been associated with an increased risk of venous thrombosis especially in women with the factor V Leiden mutation. To find an explanation for these risk differences we investigated the effects of desogestrel- and levonorgestrel-containing oral contraceptives as well as their progestagens separately on the coagulation system in the absence or presence of the factor V Leiden mutation. In a single center, double blind trial, 51 women without and 35 women with the factor V Leiden mutation were randomized to either a second generation (30 microg ethinylestradiol/150 microg levonorgestrel) or a third generation (30 microg ethinylestradiol/150 microg desogestrel) oral contraceptive. ⋯ In carriers of the factor V Leiden mutation desogestrel-containing oral contraceptives induced more pronounced changes in factor V (-14.2; 95% CI -22.4 to -6.0) and factor VII (36.1; 95% CI 19.7 to 52.6) compared to levonorgestrel-containing oral contraceptives. Comparing desogestrel- and levonorgestrel-only, only for factor V a differential effect was found in these women (-9.5; 95% CI -18.3 to -0.6). It appears that desogestrel-containing oral contraceptives have a more pronounced effect on the coagulation system than levonorgestrel-containing oral contraceptives which may be explained by a less effective compensation of the thrombotic effect of ethinylestradiol by desogestrel.