The purpose of the study was to determine the relationship between hemorheological profile, i.e. blood viscosity, and other risk factors for cardiovascular and thrombotic diseases in women taking oral contraceptives and if blood viscosity may be considered a marker of cardiovascular risk in OC users. Plasma levels of coagulation parameters, serum lipids, blood viscosity and RBC deformability were determined in a group of 10 women taking OC vs. 10 controls. The blood parameters were evaluated before OC use and thereafter at 3 and 6 months. A significant change in the partial thromboplastin time, fibrinogen, HDL and apolipoprotein A-I was observed, while the other parameters remained unchanged. Plasma viscosity was significantly increased during OC treatment; whole blood viscosity and RBC deformability remained unchanged. However, although some parameters were significantly modified during OC treatment, all alterations remained within the normal range of laboratory values. The data confirm that low-dose triphasic OC therapy does not affect significantly the coagulation system, serum lipid metabolism and blood viscosity. Plasma viscosity measurement may be considered as a marker for monitoring women using OC because it is apparently the most sensitive parameter.
PIP: Previous studies have documented an association between blood viscosity and risk factors for cardiovascular and thromboembolic disease. The present study assessed the impact of use of a low-dose, triphasic oral contraceptive (OC) containing ethinyl estradiol in combination with gestodene on the coagulation system, serum lipid metabolism, and blood viscosity. Enrolled were 10 OC users with no history of OC use before the study and 10 non-users. At 3 and 6 months after initiation of OC use, significant changes were recorded in partial thromboplastin time, fibrinogen, high density lipoprotein, and apolipoprotein A-1. Plasma viscosity was significantly increased during OC use, while whole blood viscosity and erythrocyte deformability remained unchanged. All alterations associated with OC treatment remained within the normal range of laboratory values, however. Thus, these findings suggest an absence of any significant OC effects on the hemostatic balance or lipid metabolism that might represent a risk factor for cardiovascular disease. Moreover, the measurement of blood viscosity may be a promising marker for monitoring thrombotic risk in women taking OCs given its apparent high sensitivity.