The purpose of this study was to investigate the normal lingual frenulum anatomy in newborns and to evaluate tip-frenulum distance as an objective diagnostic tool for identifying newborns at risk for anterior and posterior tongue tie and breastfeeding difficulty.
The distance from the tongue tip to the insertion of the lingual frenulum was measured in a group of 100 healthy newborns to establish normative data. The presence of a visible or palpable cord was noted. Inter-rater reliability was assessed. Breastfeeding surveys including a maternal pain scale and Infant Breastfeeding Assessment Tool (IBFAT) were administered on days of life 2 and 14 to determine whether these findings predict breastfeeding difficulty.
Mean tip-frenulum length was 9.07 mm. Intraclass correlation coefficient between observers for tip-frenulum length was 0.82. A visible cord was identified in 21 subjects (21%). A palpable cord was identified in 59 subjects (59%). Unweighted κ coefficients for inter-rater reliability of visible and palpable cords were 0.91 and 0.47, respectively. Visible cord and shorter tip-frenulum distance were independently predictive of higher maternal pain scores. A positive correlation was identified between tip-frenulum length and IBFAT scores for mothers with two or more previous breastfed children.
Tongue tip-frenulum length correlated with maternal nipple pain, and was useful as an objective tool for identifying newborns at risk for ankyloglossia. Maternal breastfeeding experience appears to be an important factor in the link between tongue anatomy and breastfeeding difficulty. The presence of a palpable cord was variable across examiners, and should be interpreted with caution when evaluating newborns for posterior tongue tie.