Hi, and thanks for your medical question on eHealth forum!
If you have Von Williebrands disease there is usually no problem in conceiving. You can go for pills to decrease the bleeding without stopping ovulation. However, you will need to be monitored very carefully both during pregnancy and after delivery.
There are drugs and platelet transfusions to stop heavy menstrual flow. Pregnancy will have to be planned in consultation with a hematologist and gynecologist. Hope this helps. Take care!