Hi emzul, they do need to run regular anti-10a tests, whatever those are. Sometimes they need to adjust your dose based on the results, but I was told this is quite rare, especially as you've probably been on tinzaparin or similar before.
As you put on weight you may need to have your dose increased, too.
In general, you should be anticoagulated throughout your pregnancy and especially 6 weeks post partum. If anyone offers to take you off medication beforehand you should seriously question them and if necessary ask for a second opinion on the matter.
As for labour, you should ask your doc. I wasn't given specifics as I never got that far, but basically you get to take a break while you are in labour and there is a minimum waiting time between your last shot and an epidural (something like 12 hours if I remember correctly - something to discuss with your doc). The effect of the injections wears off quite quickly and in any case the dose you are on isn't too high. After your initial clotting episode you'll have been on twice or three times the dose plus starting up warfarin at the same time... As an example, I've been on tinzaparin for the past year. In that time I spent three months miscarrying my first pregnancy, regularly gushing blood, passing egg-sized clots, the lot and had three further losses, which were thankfully a little less dramatic. I had to undergo four operations and for each one I took my last shot 12-24 hours before surgery and my next shot 6-8 hours after surgery. Yes, I got a bit tired and looked very pale over the first dramatic three months, but my blood count remained within the normal range and I wasn't even anaemic!
I am sure you will be fine and they will take extra special care of you with this pregnancy
Angelkissiz, how are you doing at the moment? Are you still in any pain or anything? Are they planning on following you up with another scan or something?