Second time doing this workout, and I still really like it.
Kelly, I'm not sure I'd call these pregnancy-friendly, though I don't remember any moves that have you on your back. But there's lots of plank-stuff, jumping stuff, and swinging weights (like kettlebells). It might work well if you were willing to do many of the moves sans weights. It's certainly really, really strenuous. Harder than Jillian's, I'd say. As I recall, the strength-training one does have you on your back a bit, but not much. Amazon actually has a really detailed review (move by move) of the DVDs, near the top.