Effects of progestogens on haemostasis

Area of Science:

• Reproductive endocrinology
• Vascular biology
• Hemostasis

Background:

• Epidemiological data links progestogen use in oral contraceptives to venous and arterial diseases.
• Progestogen effects on hemostasis are complex, influenced by type, dose, estrogen presence, and administration route.

Purpose of the Study:

• To elucidate the role of progestogens in the pathogenesis of venous and arterial diseases.
• To differentiate the impact of various progestogen formulations on hemostasis and vascular function.

Main Methods:

• Review of epidemiological data on oral contraceptive use and thromboembolic events.
• Analysis of studies on the effects of progestogens (alone and with estrogens) on coagulation and fibrinolysis parameters.
• Examination of the localization and function of sex steroid receptors in vascular cells.

Main Results:

• Progestogen-only preparations and hormone replacement therapy with natural estrogens showed minimal adverse effects on hemostasis.
• Ovulation inhibitors accelerated coagulation and fibrinolysis, primarily due to ethinylestradiol's effects.
• Progestogens with androgenic properties may mitigate estrogen-induced procoagulant effects.
• Progestogens differentially affect veins (increasing distensibility, potentially causing stasis) and arteries (acting as vasoconstrictors, potentially causing ischemic events).

Conclusions:

• Progestogens play a significant role in the pathomechanism of venous and arterial diseases, particularly in oral contraceptives.
• The vascular and hemostatic effects of progestogens are context-dependent, varying with formulation and individual predisposition.
• Understanding these mechanisms is crucial for assessing the risks associated with progestogen-containing therapies.