Just last week I was speaking with my cousin who is a nurse about my heavy flow. She sent me the following links:
http://kidshealth.org/parent/medical/heart/vwd.html
http://www.webmd.com/a-to-z-guides/von-willebrands-diseas...
http://www.nhlbi.nih.gov/health/dci/Diseases/vWD/vWD_What...
I've had heavy bleeding all my menstrual life. It got worse about 15 years ago (I am 42 now). I have had all the tests you mentioned and everything is "normal." I was given Provera to stop my bleeding. One menstrual cycle lasted over 90 days!!! Provera was the only thing that stopped that one. The bleeding was intense. I would stand up from a sitting position and the blood would gush out of me, soaking my clothes and the floor. This happened 3x while at work and the carpet had to be replaced. They eventually got one of those plastic floor covers just for me! Embarassing! That gushing - the only way I can explain what it was like is to relate it to when your bag of waters breaks and you go into labor. Just like that!
About 5 years ago my doctor put me on birth control pills and that has helped tremendously. I still bleed excessively, but only for 3-7 days - not 90 days! I can live with that! I just plan to stay home on those days!
I hope I didn't gross anyone out with my story. I know it was a little graphic.
(This excessive bleeding runs in my family. My 12 year old is already having these problems!)
A.