A cross-sectional study of bleeding phenotype in haemophilia A carriers

Haemophilia A carriers have historically been thought to exhibit normal haemostasis. However, recent data demonstrates that, despite normal factor VIII (FVIII), haemophilia A carriers demonstrate an increased bleeding tendency. We tested the hypothesis that obligate haemophilia carriers exhibit an increase in clinically relevant bleeding. A cross-sectional study was performed comparing haemophilia A carriers to normal women. Questionnaire assessment included a general bleeding questionnaire, condensed MCMDM-1VWD bleeding assessment tool and Pictorial Bleeding Assessment Chart (PBAC). Laboratory assessment included complete blood count, prothrombin time, activated partial thromboplastin time, fibrinogen activity, FVIII activity (FVIII:C), von Willebrand factor antigen level, ristocetin cofactor, platelet function analyser-100(TM) and ABO blood type. Forty-four haemophilia A carriers and 43 controls were included. Demographic features were similar. Laboratory results demonstrated a statistically significant difference only in FVIII:C (825 vs. 134%, P<0001). Carriers reported a higher number of bleeding events, and both condensed MCMDM-1 VWD bleeding scores (5 vs. 1, P<0001) and PBAC scores (423 vs. 1825, P=0018) were significantly higher in carriers. Haemophilia A carriers exhibit increased bleeding symptoms when compared to normal women. Further studies are necessary to fully understand the bleeding phenotype in this population and optimize clinical management.