Temporal Trends and Geographic Variation in Frenotomy Procedures Among Infants

Frenotomy is increasingly used to treat suspected ankyloglossia in infants, but the clinical value and appropriate use of this procedure remain debated.

To examine the incidence and geographic variation of frenotomy procedures and selected complications in Danish infants.

This cohort study included all infants born in Denmark from January 1, 2014, to December 31, 2024, within a universal health care system with individual-level linkage using the Danish National Health Service Register and the National Patient Registry. Matched controls without frenotomy were identified in a 1:5 ratio for comparison.

Frenotomy procedures identified through procedure codes.

Annual and age-specific incidence proportions, cumulative incidence by birth cohort, birth order, regional and municipal incidence proportions, and absolute and relative risks of bleeding, repeat procedures, and hospital contacts for feeding difficulties or failure to thrive.

Among 656 240 infants (337 110 [51.4%] male) born from January 1, 2014, through December 31, 2024, 56 737 (8.6%) underwent frenotomy within the first year of life. Infants had a median (IQR) age of 2 (0-5) weeks at the time of frenotomy. Annual incidence of frenotomy procedures increased from 5.3 (95% CI, 5.2-5.5) per 100 infants in 2015 to 12.1 (95% CI, 11.8-12.4) per 100 in 2024. Incidence was consistently higher among males than among females, with an annual incidence for males of 14.1 (95% CI, 13.7-14.5) per 100 infants and for females of 10.0 (95% CI, 9.6-10.3) per 100 infants in 2024. The cumulative incidence increased from 4.5 (95% CI, 4.4-4.6) per 100 infants in the 2014 to 2017 birth cohort to 12.0 (95% CI, 11.8-12.1) per 100 infants in the 2021 to 2024 cohort. Most procedures were performed in private practice settings (91.2 of 100 infants [n = 51 746 of 56 737]) by otolaryngologists (92.3 of 100 infants [n = 52 380 of 56 737]). Geographic variation in cumulative incidence was significant, with municipal incidence ranging from 4.2 [95% CI, 2.5-7.0] per 100 infants to 36.1 [95% CI, 30.6-42.0] per 100 infants in 2024. Severe complications were rare. Bleeding within 30 days of the procedure occurred in 11 of 56 737 infants (0.02%) undergoing frenotomy vs 13 of 274 476 matched controls (0.005%) (risk ratio, 4.1; 95% CI, 1.9-9.3), and repeat procedures were performed in 3585 (6.3%). Hospital contacts related to feeding difficulties or poor weight gain were more common among infants with a frenotomy procedure than controls.

In this cohort study, the rate of frenotomy among Danish infants significantly increased in the past 10 years, with most procedures performed early in life and considerable variation in geographic region. Given limited evidence on the effectiveness of frenotomy for ankyloglossia, these findings highlight the need for improved implementation of evidence-based treatment and further evaluation of the clinical appropriateness of widespread frenotomy in infancy.