IR can be great for pregnancy - it tends to minimize stretch marks.

What you shoot really depends on what the pregnant woman wants. I like lots of skin, but have done pregnancy shoots where all clothes remained in place. I've shot the "hands making a heart" on the belly because I was asked to. I introduce my own ideas as well, but the client is in charge. Here's some of my pregnancy stuff (there's more in my gallery and tons more in my files here):

And my favorite labour shot. Lucky enough to have great light and a lovely mother who doesn't mind sharing this image: