Estrogens, progestogens and thrombosis

Abstract

Summary. Hundreds of millions of women worldwide use either oral contraceptives or postmenopausal hormone replacement. The use of oral contraceptives leads to an increased risk of venous thrombosis, of myocardial infarction, of stroke and of peripheral artery disease, the risks of which are highest during the first year of use. Women with coagulation abnormalities have a higher risk of venous thrombosis when they use oral contraceptives (or postmenopausal hormones) than women without these abnormalities. The risk of venous thrombosis is also higher for preparations containing desogestrel or gestodene (third‐generation progestogens) than for those containing levonorgestrel (second‐generation progestogens). A previous thrombosis as well as obesity also increase the risk of oral contraceptive‐related thrombosis. Hormone replacement therapy increases the risk of venous thrombosis, and has no beneficial, and possibly even a detrimental, effect on the risk of arterial disease. The risk of arterial disease in oral contraceptive users and users of hormone replacement therapy is at most weakly affected by the presence of prothrombotic abnormalities.

Contracepção hormonal e sistema cardiovascular

“…There is also an increase in coagulation factors (fibrinogen, VII, VIII, IX, X, XII and XIII) and a reduction in natural coagulation inhibitors (protein S and antithrombin), which produces a mild procoagulant effect 8,9 . These effects can be seen more clearly in tests that assess the overall hemostasis.…”

“…The high dose of EE (≥ 50 mcg) is associated with a twofold increase in risk of VTE when compared to a low dose of this hormone (<50 mcg) 9,11,12 . Recently, it was said that formulations containing 20 mcg of EE were associated with lower risk of thrombosis (OR: 0.8; 95% CI: 0.5-1.2) when compared to preparations with 30 mcg of EE, but without any significant difference in the EE dose of contraceptives (150 mcg for 15-20 mcg).…”

Hormônios femininos e hemostasia

“…Já o sistema fibrinolítico atua sobre a fibrina formada no local da lesão vascular, degradando-a e estabilizando o coágulo. Desta forma, em condições normais, os mecanismos anticoagulantes prevalecem sobre os pró-coagulantes (Figura 1) 5 .…”

Human platelets differentially concentrate estradiol, estrone and testosterone

“…Hormone therapy and oral contraceptives increase the risk of ischemic stroke and venous thrombosis [1][2][3]. Platelet estrogen receptor expression suggests that platelets may directly mediate this elevated risk [4,5].…”

“…Yet ex vivo platelet aggregation studies in patients receiving fluoxetine have yielded conflicting results, with some studies showing decreased platelet aggregation and others showing no effect [2]. Several epidemiological studies indicate that fluoxetine use is associated with impaired hemostasis, particularly gastrointestinal bleeding [3]. The possibility that SSRIs may also confer protection from myocardial infarction, even compared to other classes of antidepressants, has also been demonstrated in some clinical studies [4].…”