Factor VIII and von Willebrand factor changes after desmopressin and during pregnancy in type 2M von Willebrand disease Vicenza: a prospective study comparing patients with single (R1205H) and double (R1205H-M740I) defect.

BACKGROUND: Type 2M von Willebrand disease (VWD) Vicenza is characterized by the presence of ultra-large von Willebrand factor (VWF) multimers in plasma and very low factor VIII (FVIII)/VWF measurements. So far, R1205H mutation, alone or associated with M740I defect, has been constantly detected in these patients. No data on FVIII/VWF changes after desmopressin and during pregnancy in patients with phenotypic VWD Vicenza has been reported. OBJECTIVE: To evaluate biological responsiveness to desmopressin, the FVIII/VWF changes during pregnancy and the clinical outcome in pregnancies and deliveries of six primipara with type 2M VWD Vicenza prospectively followed. PATIENTS AND METHODS: Three women with single (R1205H) and three with double (R1205H and M740I) mutation in the VWF gene were enrolled in the study. Prior to pregnancy, all patients had undergone desmopressin test-infusion to assess biological responsiveness and its possible clinical usefulness. RESULTS: The results of test-infusion with desmopressin showed the full normalization of FVIII/VWF measurements, with rapid clearance of all moieties postinfusion. However, FVIII/VWF measurements in patients with double defect remained greater after 4 h than those of patients with single defect. The severely reduced basal FVIII/VWF measurements did not change during pregnancy, although somewhat higher VWF levels were observed in patients with double defect. Five out of six women underwent successful delivery under desmopressin prophylaxis, without immediate or delayed bleeding and only one was given a FVIII/VWF concentrate because of a cesarean section. CONCLUSIONS: Delivery in women with VWD type 2M Vicenza is safely managed by using desmopressin, despite the fact that basal low FVIII/VWF is not significantly increased during the pregnancy.