Upper Lip Frenulum Findings and Breastfeeding Problems in Healthy Newborns.

Importance: Breastfeeding improves health outcomes in neonates. However, infants' oral anatomy may alter latch and sucking mechanics, hampering breastfeeding. The role of maxillary frenulum (upper lip-tie) has remained controversial. Objective: To investigate the association between upper lip-tie clinical findings, such as thickness, attachment, and upper lip mobility, and early breastfeeding problems. Design, Setting, and Participants: In this prospective cohort study (Lingual Frenulum in Newborn Infants substudy), consecutive mother-infant dyads were studied from August 2, 2023, to January 31, 2024, in the mother-child unit of Oulu University Hospital, Oulu, Finland. After 6 months, parents were asked about breastfeeding success. Main Outcomes and Measures: Main outcomes were the association of various maxillary frenulum clinical findings with breastfeeding problems and possible treatment indications. Study physicians assessed frenulum thickness, tissue type, attachment point, upper lip mobility and skin paleness when stretched, sucking pad, mother's need to fix the upper lip position, and the need of early tongue-tie treatment. The validated maternal breastfeeding experience scores were recorded. Follow-up information was inquired via emails. Results: Of the 264 studied mother-infant dyads (151 [57.2%] male infants; mean [SD] gestational age, 39.5 [1.2] weeks), 228 mothers (86.4%) reported early breastfeeding problems in maternal breastfeeding experience scoring. Baseline data were similar between the breastfeeding problem group vs controls. No associations between distinct maxillary frenulum findings and breastfeeding problems were found. Mothers without breastfeeding problems had more often previous breastfeeding experience than mothers who reported breastfeeding problems (28 [77.8%] vs 116 [50.9%], P = .003). Of the mothers with infants treated early for tongue-tie, 17 (43.6%) vs 46 (20.8%) of the nontreated patients' mothers reported a need to fix the upper lip position during breastfeeding (P = .003). The upper lip-ties of 4 infants (1.5%) had been operated on during the 6-month follow-up period. Conclusions and Relevance: In this prospective cohort study, an isolated, harmful upper lip-tie was rare in newborn infants. Maternal inexperience, rather than infant's upper lip-tie anatomy, was associated with breastfeeding problems; no operative treatment indications for maxillary frenulum were confirmed.