Oral contraceptives, fibrinogen and cardiovascular risk

Today there can be little doubt about the fact that fibrinogen is a major, independent cardiovascular risk factor. Therefore one should consider circumstances that might lead to an increment of plasma fibrinogen levels. Oral contraceptives (OCs) have been reported to be associated with high fibrinogen. The present review details the information on this potentially important side effect. Cross sectional studies report both increased fibrinogen in OC users as well as no such change. Longitudinal studies yield a much clearer picture. They demonstrate that OCs lead to a significant rise in fibrinogen within 1-3 months of medication. The effect seems to be strongest in OCs with a high oestrogen concentration. Upon discontinuation, fibrinogen returns to normal, usually within about 3 months. These findings suggest that OC use might contribute to the cardiovascular risk partly by elevating fibrinogen levels.