If you're buying fancy baby clothes as a gift for someone, I strongly recommend buying something larger than a "newborn" size.
This tip brought to you by the start of reorganizing SteelyKid's dresser, and the discovery that several gift outfits must be packed away completely unworn, because at six and a half weeks she's already outgrown them.
(They've been unworn because they include pants, which we find less convenient, or long sleeves, which until recently it's been too warm for; also because fancy clothes seemed like overkill for just hanging out at home. If I'd realized how fast she'd outgrow them, though, I'd have made a point of putting her in them all at least once, just because.)