HI, I can't speak to the overarching issue...that is something for a doc to discuss w/ you certainly. However, I had a very large DVT that stretched from my groin to my knee in my last pregnancy (he's 6.5 now) and am pregnant again. You won't likely be on Coumadin during pregnancy (I'm guessing) but they'll switch you to Heparin or Lovenox (I'm on Lovenox). I would presume your chances for success and health depend on your history and what happened previously during pregnancy and what complications you either had or didn't have. My clot was an isolated occurence and they've not found a clotting disorder or other disorder to be present. Based on my circumstance, my high-risk OB today, in fact, told me that he's increasing my dose (because it's time to as I'm 26 weeks along) but that my risk of having another clot while anticoagulated is very, very small.
We waited for 6 years to conceive because we were so afraid that I might develop another clot and that I wouldn't be so lucky this time around, but the doc has put us at tremendous ease.
So, talk to a Perinatologis / High-Risk OB / Maternal Fetal Specialist along with your Hematologist to get the best picture.
Good luck!
I also have a clotting disorder (compound heterozygous MTHFR). Mine is not so severe that I need blood thinners but I have heard of people on them and they do seem to work well. Were you on them with your other children? My understanding of blood clotting disorders is that you were born with them. Maybe you won't need to take the blood thinners if you never had to take them before. Good luck!