No it is ok. Clexane is fine for pregnant women or else they wouldn't be prescribing it to you. I have a Biomedical Science background and worked in conjunction with a clinic which had numerous pregnant women with DVT. Heparin is also fine or even Arixtra.
Many thaks for your respons
My baby boy is 11 weeks monday, i had to use clexane from 6 weeks pregnant until 6 weeks after the birth. It has done him no harm, you'll be fine.