Estrogen thromboembolism from

Many systemically administered estrogen products are available in the United States, but conjugated equine estrogens (CEEs), prepared from the urine of pregnant mares, is the most widely prescribed. Transdermal estrogen preparations are also available and usually are prescribed for patients who experience adverse effects, elevated triglycerides, or liver function abnormalities while taking an oral product. Transdermal preparations also have a lower incidence of venous thromboembolism than oral preparations.9... 

This strategy is based on evidence that the most serions side effects of combination OCs (i.e., thromboembolic events, stroke, or MI) result from excessive estrogen content." 3.24... 

Progestin-only minipill preparations do not increase thromboembolic events or blood pressure or cause nausea and breast tenderness. Acne may result from the androgenic activity of norethin-drone-containing preparations. These preparations may be attractive for nursing mothers because they do not decrease lactation as do products containing estrogens. 

Although the adverse effects of OC therapy include an increased risk of stroke, acute myocardial infarction, and venous thromboembolic disease, the incidence of cardiovascular disease in this patient population (age, <35 years) is already low (66). In women older than 35 years, the natural incidence of cardiovascular disease increases, so these adverse effects become more important to consider. From a metabolic perspective, the primary adverse effect of the estrogen component is an increase in hepatic production of proteins, including those that enhance venous and arterial thromboembolism (70). In addition, the progestin component has an adverse effect... 

The relatively high incidence of thromboembolic phenomena in women on the pill prompted an examination on the effects of the estrogenic and/or progesteronic components in the pill on the surface charge characteristics of the vascular system. Electrophoretic mobilities of erythrocytes and platelets and blood coagulation times were determined with samples of blood drawn from 33 women on the pill and 30 control subjects. The electrophoretic mobilities were reduced thrombin recalcification times were not affected but thrombin times and partial thromboplastin times were shortened. 

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