I love my Ergo but looking at the bubba moe I think it would be more suitable with a pg belly. I wear the Ergo right around my middle and I just don't see how the back carry would work with a pg belly comfortably, you can wear the ergo around your hips but I don't find it as comfortable.

Does your sister carry her 2yo in the bubbamoe? How does she find it distributes the weight? The ergo is excellent for making heavy weights feel like light weights but it's not going to be much use to you if you can't wear it for the next 20wks :-)