TY - JOUR
T1 - Thyroid function, activated protein C resistance and the risk of venous thrombosis in users of hormonal contraceptives
AU - Raps, M.
AU - Curvers, J.
AU - Helmerhorst, F. M.
AU - Ballieux, B. E. P. B.
AU - Rosing, J.
AU - Thomassen, S.
AU - Rosendaal, F. R.
AU - van Vliet, H. A. A. M.
PY - 2014/4
Y1 - 2014/4
N2 - Introduction: Use of combined hormonal contraceptives is associated with a three-to eight-fold increased risk of venous thrombosis compared with non-use. The thrombotic risk depends on the estrogen dose as well as the progestogen type. Use of hormonal contraceptives leads to resistance to activated protein C (APC), which may serve as marker for the risk of venous thrombosis. Hyperthyroidism is also associated with an increased risk of venous thrombosis, due to increased free Thyroxine (FT4) levels which cause a hypercoagulable state. Materials and methods: The objective of this study was to evaluate the effects of hormonal contraceptives on levels of FT4, thyroid stimulating hormone (TSH) and thyroxine binding globulin (TBG), and to investigate the effects on APC resistance per contraceptive group. We measured FT4, TBG and TSH levels and APC resistance in 231 users of oral contraceptives. Results: Users of the most thrombogenic hormonal contraceptives, i.e. containing desogestrel, cyproterone acetate or drospirenone, had higher TBG levels than users of less thrombogenic hormonal contraceptives, i.e. the levonorgestrel-containing intrauterine device. TSH levels were not significantly elevated and FT4 levels did not change. TBG levels were also associated with APC resistance. Conclusion: Use of hormonal contraceptives lead to elevated TBG levels, slightly elevated TSH levels and unchanged FT4 levels without causing a hyperthyroid state. Thus, the increased thrombotic risk during the use of hormonal contraceptives cannot be explained by a hyperthyroid state caused by use of these hormonal contraceptives.
AB - Introduction: Use of combined hormonal contraceptives is associated with a three-to eight-fold increased risk of venous thrombosis compared with non-use. The thrombotic risk depends on the estrogen dose as well as the progestogen type. Use of hormonal contraceptives leads to resistance to activated protein C (APC), which may serve as marker for the risk of venous thrombosis. Hyperthyroidism is also associated with an increased risk of venous thrombosis, due to increased free Thyroxine (FT4) levels which cause a hypercoagulable state. Materials and methods: The objective of this study was to evaluate the effects of hormonal contraceptives on levels of FT4, thyroid stimulating hormone (TSH) and thyroxine binding globulin (TBG), and to investigate the effects on APC resistance per contraceptive group. We measured FT4, TBG and TSH levels and APC resistance in 231 users of oral contraceptives. Results: Users of the most thrombogenic hormonal contraceptives, i.e. containing desogestrel, cyproterone acetate or drospirenone, had higher TBG levels than users of less thrombogenic hormonal contraceptives, i.e. the levonorgestrel-containing intrauterine device. TSH levels were not significantly elevated and FT4 levels did not change. TBG levels were also associated with APC resistance. Conclusion: Use of hormonal contraceptives lead to elevated TBG levels, slightly elevated TSH levels and unchanged FT4 levels without causing a hyperthyroid state. Thus, the increased thrombotic risk during the use of hormonal contraceptives cannot be explained by a hyperthyroid state caused by use of these hormonal contraceptives.
U2 - 10.1016/j.thromres.2013.12.041
DO - 10.1016/j.thromres.2013.12.041
M3 - Article
C2 - 24438944
SN - 0049-3848
VL - 133
SP - 640
EP - 644
JO - Thrombosis Research
JF - Thrombosis Research
IS - 4
ER -