wow I posted this some time ago!
I had my son (and my DVT) in 2002! I have since had a daughter in 2008 and another daughter this May (2011)
I also had a severe DVT and only just made it, I spent the remainder of my first pregnancy on Heparin and being unable to walk so was obviously very worried about my next pregnany hence the post.
On my 2nd pregnancy I went on the heparin/tinzaparin as a precaution, one injection everyday until I gave birth and regular check ups for platelet counts etc. The birth was a planned induction so they could monitor me closely. Unfortunately this ended in complications, but nothing to do with the DVT and baby was fine 
On my 3rd pregnancy I was started on the Tinzaparin at 6 weeks and had 2 injections every day throughout the pregnancy and for 6 weeks after this time.
For this delivery, I decided on a planned C-Section due to the complications last time. (I still ended up with complications) again, nothing to do with DVT.
There is no reason why you couldnt go on to have a normal pregnancy and delivery, its just me, I am not good at being pregnant and giving birth!
Good luck
xxx