R.M.
C.,
My son is three as well and he doesn't always get out of bed, but sometimes he will try us. When we first put him in the big bed is was awful. We had to take him back about 30 times or more every night for about 1 1/2 weeks. When he walked out of his room we would just take him back to bed everytime. He would kick and scream and cry, but now he is much better. A lot of it is his age. At three they push the boundries to see what they can get away with. You need to stay firm. I know you're tired b/c your pregnant. Just start the process earlier b/c it's going to take a while then whenever he is more compliant you can move it back to the normal time. Just keep in mind that he has you figured out and he knows exactly how much you will take so be strong and don't give in. With a baby on the way you need to nip it in the bud now!!! I know I was pregnant with our third when I faced this with my 3 year old. It will pass!!
If you're not a part of some kind of mom's support group try is out. It is helpful to talk to moms going thru similur situations. Try www.mops.com to look for a group near you.
God Bless,
R.