Hi Kazzle
I had to give myself Clexane injections (same as Heparin) for 6 weeks after the birth of my son.  Also have to have them anytime I fly for more than 8 hours.  I have high Factor 8, which basically means my blood clots way more than normal.  And cause your body clots more after pregnancy, to stop the bleeding etc, I had to have the injections to ensure I didn't end up with a blood clot.  Feel free to ask any questions or PM me for more details.
Amanda