Mel, Maybe opt for the infant size. I can do them with Snaps if you prefer. I haven't made up a heap of teh infants only doing them as their ordered really so I don't have aheap sitting here. But LMK. I think the NB size really deponds on the baby. Maz had mat in them for a while yet Jodie's little porker went straight intot he infant size LOL. I would say the NB is up to 5kg.