Heparin and Clexane (the injections that are most commonly given) can be used after major surgery if the patient is likely to be immobile for a period of time (longer than 12hrs)
We give these to back and brain surgery patients and also some of the other major surgeries...
Although a c/s is major surgery the fact that you are moving about the next day decreases the likelihood of getting a DVT. Just by wriggling your toes and deep breathing and coughing hourly initially and then 4 hrs if you are bed bound will decrease this risk.
But usually as we have had a baby, the last thing that you want to do is lie in bed all day (well thats what i found anyway, i wanted to move and hold and change and feed my beautiful girl (despite the pain)

I didnt have any anticoagulants after having MJ via emerg c/s

Hope this helps