Squats well pregnant is not a good idea. Leg ext when done correctly with the right weight etc in a steady controled manner are not bad IMO the problem is most people load up the ext and fling there legs about that will fack up a knee for sure.
You might want to check out my leg routine right now
http://www.elitefitness.com/forum/w...2011-superqt-sees-her-abs-again-730037-3.html post 45 this is what I am doing tell my ankle is back to 100% not doing anything for calves because of the ankle I could do toe taps with no weight that actually might be a good idea. LOL Anyways for you seated calf raises and single leg standing calf raise maybe hold a db in one hand.
Something like these for calves
Single Leg Calf Raise
or this
Cable Single Leg Calf Raise