Tongue-tie (ankyloglossia) is where the strip of skin connecting the baby's tongue to the floor of their mouth is shorter than usual. Some babies who have tongue-tie don't seem to be bothered by it. In others, it can restrict the tongue's movement, making it harder to breastfeed. Tongue-tie is sometimes diagnosed during a baby's routine newborn check, but it's not always easy to spot. It may not become apparent until your baby has problems feeding.