VWF and ovarian hyperstimulation syndrome: In addition, increase in the levelsof both coagulation factors (such as Von Willebrandfactor (vWF), factors VIII and V, and fibrinogen)and protein C-S activity, while decrease inantithrombin-III (AT-III) during controlled ovarianhyperstimulation are responsible for complications.Venous thromboembolism (75%) is commonlyfound more than arterial thromboembolism(25%) in following ovarian stimulation for ART,and also it is shown in up to 95% of cases associatedwith OHSS (2).