Re: heparintherapy risks
I had issues with that before too and will probably have to be on heparin during pregnancy. I did some research and it doesn't look like heparin will affect the baby because it doesn't cross the placenta. You do have to give it to yourself in the form of a shot. I do think there are will be issues when it comes time to deliver though. I couldn't find much about it, but the little I did find said that you would have to be induced and to not take heparin so many hours (or days?) before so there aren't any bleeding problems.
Whether or not it is necessary will be determined by your doctor. I have no genetic tendencies either, my problem was caused by the estrogen in BC pills, but I would be a little less paranoid if I were to take the heparin. I really don't want blood clots again.
Hope this helps.