Yup Miss M was nearly 9 pound born - but she was long and skinny - and stayed that way. I went straight from the mother-ease newborn cover into the medium with her - but a chubbier bub might be fine in the smalls for ages. You never know unless they are here really!
Oh - and cushie tushies promote themselves as an AIO, but are technically an AI2 because of the snap in layer :)

