Check that the nappy is fastened properly, not too tight but not too loose, by testing that you can fit two fingers inside the waistband. If the nappy doesn't cover your babies bottom, regularly becomes soaking wet, or you see red marks or signs of chafing, this may mean the nappy is too small for your baby and it's time to move up to the next nappy size.
Here's a handy guide for Pura nappies:
