The risk of venous thrombosis (VT) varies according to the type of progestogen that is found in combined oral contraceptives (COCs). When combined with the estrogen component ethinylestradiol (EE),... Show moreThe risk of venous thrombosis (VT) varies according to the type of progestogen that is found in combined oral contraceptives (COCs). When combined with the estrogen component ethinylestradiol (EE), the androgenic progestogens are better able to counteract the EE-induced stimulation of liver proteins and hence are associated with a twofold decreased risk of VT compared with non- or antiandrogenic progestogens, which exert limited counteraction of EE. Because EE is responsible for the increased risk, novel estrogens such as estradiol were developed and seem to have a lower risk of VT than EE. Besides COCs, there are other methods of hormonal contraceptives, such as progestogen-only contraceptives, which do not increase VT risk, except for injectables. Other nonoral contraceptives are combined vaginal rings and patches. There is insufficient evidence regarding the risk of VT associated with these two methods compared with COCs. The increased risk associated with COCs is more pronounced in women with inherited thrombophilia. In these women, the progestogen levonorgestrel seems to be associated with the lowest risk of VT. Currently, there are no studies that have investigated the risk of VT in women who switch COCs. We hypothesize that switching COCs, even when switching from a high- to a low-risk COC, increases the risk of VT. Finally, risk prediction models in women who use COCs are lacking. Since there is a large number of VT cases associated with COC use, it is important to identify women at risk of VT and advise them on alternative contraception methods. Show less
It is not known whether the synergistic effect of genetic markers, increasing the risk of venous thrombosis (VT), and combined oral contraceptives (COC) use varies between different types of... Show moreIt is not known whether the synergistic effect of genetic markers, increasing the risk of venous thrombosis (VT), and combined oral contraceptives (COC) use varies between different types of progestogens in these preparations. We investigated the joint effect of genetic risk factor, that is, F5 rs6025, F2 rs1799963, and FGG rs2066865 mutations, and different progestogens on the risk of VT. The constrained maximum likelihood estimation (CMLE) method was used to calculate joint effects, expressed as odds ratio (OR) with 95% confidence intervals [CI]. As the dose of estrogen is known to be a risk factor for VT, analyses were restricted to COC with 30 mu g estrogen and each progestogen. Overall, the joint effect of COC and genetic variants was lowest for COC containing the progestogen levonorgestrel, albeit CIs were wide. The OR (95% CI) of the four different analyses (i.e. joint effect with F5 rs6025, F2 rs1799963, F5 rs6025 or F2 rs1799963 and FGG rs2066865) ranged between 7 center dot 4 (5 center dot 4-10 center dot 2) and 24 center dot 8 (12 center dot 3-50 center dot 0) for levonorgestrel. For gestodene the joint effect ranged between 11 center dot 7 (7 center dot 2-19 center dot 1) and 30 center dot 9 (10 center dot 6-89 center dot 9). Desogestrel and cyproterone acetate had the highest risk estimates: 14 center dot 6 (9 center dot 7-21 center dot 9) and 32 center dot 6 (13 center dot 2-80 center dot 6) and 15 center dot 5 (9 center dot 7-24 center dot 9) and 44 center dot 4 (16 center dot 9-116 center dot 3) respectively. In women with inherited thrombophilia, COC containing levonorgestrel were associated with the lowest risk of VT, albeit the CIs were wide. Show less