Study finds no link between newborn upper lip frenulum structure and breastfeeding difficulties

The study, published in JAMA Network Open, followed 264 mother–infant pairs at Oulu University Hospital between 2023 and 2024. Researchers assessed the anatomy and mobility of the upper lip frenulum in healthy, full-term infants and compared the findings with mothers’ reported breastfeeding experiences.

Overall, 86% of mothers reported experiencing breastfeeding difficulties during the first days of breastfeeding. However, the researchers found no association between the anatomical characteristics of the upper lip frenulum and breastfeeding problems. The thickness of the frenulum, its attachment site, or other structural features did not increase the risk of breastfeeding difficulties.

Instead, previous breastfeeding experience appeared to be beneficial for breastfeeding. Breastfeeding problems were reported less frequently among mothers with experience of breastfeeding previous children.

According to the researchers, an upper lip frenulum that interferes with breastfeeding is a rare finding. Nevertheless, the number of lip-tie release procedures has increased in several countries in recent years, despite limited evidence supporting their benefits.

“Breastfeeding difficulties in newborns should always be assessed comprehensively,” said paediatrician and neonatologist Outi Aikio. “Based on our findings, we found no evidence to support upper lip frenulum surgery in healthy, full-term infants. Instead, I would emphasise the importance of high-quality breastfeeding support, particularly in the early weeks after birth, when breastfeeding challenges are common.”

Research article: Niemelä L, Lohi V, Aitamurto S, Lehtinen A, Aikio O. Upper Lip Frenulum Findings and Breastfeeding Problems in Healthy Newborns. JAMA Netw Open. 2026;9(5):e2613308.