You can use any paint as long as you work slowly and keep all the windows open. I personally though went with the paint they sell at pottery barn kids since its supposed to be safe during pregnancy.
I can't remember which brand I got for the nursery, but the important part is that its zero VOC. It does make it more expensive (the paint I got was about 2x as much as "normal paint), but it meant that I could be involved in painting the room instead of having someone else do it. It was nice too that it had virtually NO smell, which meant I didnt' get nauseaus from it! Just ask at your local Lowes, or paint store for a zero VOC paint, and they'll be able to point you in the right direction.
As long as you keep the room well ventilated and don't stay in there for hours I think you'll be fine. Just take breaks, make sure you're staying hydrated and not over doing it, hard to do when painting, but you know what I mean, lol.