Importantly, in most patients with type 1 von Willebrand disease who would respond to DDAVP, factor levels will have increased during pregnancy, but in patients with type 2 and type 3 von Willebrand disease, who have the greatest need for elevation of von Willebrand factor levels, the response to DDAVP is generally poor.27 As such, if treatment is needed, administration of von Willebrand factor‐containing concentrates is recommended in the antenatal treatment of von Willebrand disease, although DDAVP may be a suitable alternative in women who are carriers of haemophilia A. This evidence concerns the gene VWF and hemophilia A.