Markers of platelet activation, thrombin generation and fibrinolysis in women with sickle cell disease: effects of differing forms of hormonal contraception

Objective: To examine laboratory markers of platelet activation, thrombin generation and fibrinolysis in women with sickle cell disease (SCD) using the combined oral contraceptive pill (COCP), progestogen only (PO) contraception and non-hormonal contraception. Design: A prospective observational study set in two teaching hospitals in the London region. Method: Forty-four women with SCD in steady haematological state using differing hormonal contraception were recruited and venesection was performed at standardised times for the measurements of markers of platelet activation, thrombin generation and fibrinolysis. Outcome measures: Prothrombin fragment(1+2) , plasmin alpha 2 antiplasmin complexes, platelet factor 4 (PF-4), beta -thromboglobulin and free protein S antigen (PS-Ag). Results: PS-Ag was decreased and PF-4 increased in all women while the other haemostatic variables were within normal reference ranges. However, there was no statistically significant differences in the measurements of all the haemostatic variables between the three groups of sickle cell women (Kruskal-Wallis, P > 0.05). Conclusion: There is anxiety about prescribing the COCP in women with SCD based on the assumption that risk of venous thromboembolism may be compounded by the underlying disease process that occurs with these women. The observed data suggest that SCD women who use the COCP have haemostatic markers which are not statistically different compared with similar women who use PO contraception or non-hormonal contraception. However, a randomized interventional trial would be necessary to evaluate further the safety aspect of COCP use in this group of women.