Make sure that the little "frills" that go around his legs are pulled out so that the elastic seam of the nappy is sitting snuggly around his thighs. I would definitely be considering going up to the next size nappy too. My DD is 4.5 kgs now and she is in the infant size.

Now, if someone could tell me how to stop newborn pooplosions that go all over everything I'd be grateful!!