The study is a prospective multi-centre clinical follow-up study of prevalence and severity of tongue-tie in neonates in Norway. During one year around 2600 newborn infants will be examined for tongue-tie in the two participating hospitals. The infants diagnosed with a tongue tie, will be followed to assess the proportion of infants treated and the severity. Feeding outcomes will be observed up to 6 months of age.

A tongue-tie may cause problems for child and mother. There are no previous studies from Norway that have assessed the magnitude and severity of tongue-tie in infants. The prevalence of tongue-tie in Norway and to what degree it influences mother and child health is unknown. It is of great importance to address a problem with possible negative effect on breastfeeding and maternal and child health. Current clinical practice varies due to incomplete knowledge of the condition. An unknown proportion of infants with tongue-tie may not be diagnosed or receive treatment. Current international research recommends treatment of tongue-tie if it causes breastfeeding problems. This project will add significant knowledge about tongue-tie in Norway.

The project supports:

• Filling knowledge gaps by researching the prevalence and severity of the condition.
• Obtaining new knowledge for the health services by establishing assessment of tongue-tie prevalence in Norway. This can be used for planning of the healthcare services.
• Improving existing practice by describing the condition and implementing best practice diagnosis and treatment.
• Creating societal benefits by improving infant nutrition and maternal health.

During the year of the study, the pediatricians at each hospital will assess the prevalence of tongue-tie in all newborn infants in their hospital. The examination will be part of the standard newborn examination which usually takes place during the 2nd day of life. A simple and short registration form will be filled out electronically, noting the type of tongue-tie and symptoms for each infant with the diagnosis. In addition, the diagnosis Ankyloglossia Q38.1 will be registered in the electronic journal system. The examination of the infant's mouth is completely safe and is already performed to asses if there is a cleft palate. The pediatrician will examine the area under the tongue in addition to the palate. All newborn infants will be examined to obtain a trustworthy prevalence. If a frenotomy is required and performed, this will be registered in the registration form and the procedure code for frenotomy EJC 20 will be registered in the electronic journal system. The breastfeeding self-efficacy tool (BSES-SF) is used for patient reported outcome measures.as well as WHO's breastfeeding indicators

To map the severity determining any possible consequences a tongue-tie may have for breastfeeding and infant nutrition the investigators will follow-up a cohort of tongue-tied infants to register if the feeding, growth, thriving and speech of the infant/child is affected by a tongue-tie.

Inclusion Criteria:

• Subject must be born in a participating hospital during the study period.
• Subjects that are recruited for follow-up must have a diagnose of tongue-tie as determined by the pediatrician in the hospital.
• Infants with a tongue-tie that have been treated with a frenotomy and infants that have not received treatment.

Exclusion Criteria:

• Infants where the parents do not wish to participate in the study or where the parents do not to understand English or Norwegian.

Infants 0 days to 2 weeks old diagnosed with a tongue tie in the counties of Telemark and Vestfold during the study enrollment period September 2019 - August 2020.