Tongue-tie surgery in babies is facing renewed scrutiny in Finland, where researchers are trying to determine which newborns actually benefit from the increasingly common procedure. A large study at the University of Oulu is examining 1,559 mother-infant pairs, while another Finnish study published this year found no evidence that the anatomy of the upper lip frenulum explains breastfeeding problems in healthy newborns.
The debate concerns frenotomy, a procedure in which the lingual frenulum, the band of tissue connecting the tongue to the floor of the mouth, is cut. A tight frenulum, known as ankyloglossia or tongue-tie, can restrict tongue movement and in some cases interfere with breastfeeding.
The difficulty is determining when the frenulum is actually responsible for the problem. Many babies with an apparently tight tongue-tie feed without difficulties, while breastfeeding problems can have several other causes.
A Finnish study is looking for the babies who actually benefit
Outi Aikio, a specialist in paediatrics and neonatology at Oulu University Hospital, is leading an ongoing study that aims to identify babies who have both a restricted tongue-tie and genuine feeding problems, and to assess whether surgery improves outcomes.
According to a new report by Yle, the project includes 1,559 mother-infant pairs and is now in the analysis phase. Results are expected during the winter of 2026-27. Aikio said previous studies have often involved relatively small groups and have been difficult to blind, making it harder to establish how much of the reported improvement can be attributed to the procedure itself.
The research comes as tongue-tie procedures have become increasingly common in Finland. Data from the Finnish Institute for Health and Welfare (THL) previously cited by Yle showed that operations involving children under one increased from 385 in 2021 to more than 600 in 2023. The increase was particularly strong in private healthcare, where the number rose from fewer than 50 to around 350.
The Finnish Paediatric Society (Suomen Lastenlääkäriyhdistys) has warned about overdiagnosis, medicalisation and treatments that are not adequately supported by evidence. Its position is that families should first receive sufficient support with breastfeeding and feeding, and that surgery should have a clear justification.
Research also questions upper lip frenulum surgery
A separate Finnish study published in JAMA Network Open in May 2026 examined whether the structure of the upper lip frenulum was associated with breastfeeding difficulties.
Researchers at the University of Oulu and Oulu University Hospital followed 264 mother-infant pairs. Although 86.4% of mothers reported some breastfeeding difficulties in the first days after birth, researchers found no significant association between those problems and the thickness, attachment point or other anatomical characteristics of the upper lip frenulum.
The study concluded that an isolated problematic upper lip-tie was rare among healthy, full-term babies. Previous breastfeeding experience among mothers was more strongly associated with fewer feeding difficulties than the anatomy of the upper lip frenulum.
Aikio said the findings provided no evidence-based indication for routinely operating on the upper lip frenulum of healthy, full-term infants and instead emphasised the importance of breastfeeding support.
Tongue-tie surgery has also increased elsewhere in the Nordics
The Finnish debate is part of a wider Nordic discussion. Denmark, where NordiskPost has previously reported on the growing use of frenotomy, now has some of the clearest evidence of how widespread the procedure has become.
A nationwide Danish study published in 2026 analysed 656,240 infants born between 2014 and 2024. Of them, 56,737, or 8.6%, underwent a frenotomy during their first year of life. The annual rate increased from 5.3 procedures per 100 infants in 2015 to 12.1 per 100 in 2024. More than 91% of procedures were performed in private practices.
The geographical differences were particularly large. In 2024, the proportion of infants undergoing frenotomy ranged from about 4% to 36% depending on the municipality, a variation the researchers said strengthened the case for more consistent, evidence-based assessment criteria.
Norway has followed a more explicitly standardised approach. In 2019, around 2.8% of Norwegian infants were diagnosed with tongue-tie and 2.2% underwent frenotomy. Norwegian interdisciplinary guidelines recommend breastfeeding counselling first when feeding problems occur, with surgery considered when those measures do not resolve the problem.
In Sweden, national health information similarly states that a short or tight frenulum does not necessarily require treatment. Regional guidance estimates that around 5-10% of children are born with a short frenulum, but notes that most do not develop symptoms. Surgery may be considered for infants when restriction of the tongue is accompanied by breastfeeding problems. Comparable national data on the number of Swedish frenotomies are not readily available.
The controversy extends beyond the Nordic countries
The procedure is also common elsewhere in Europe. England’s 2024 Infant Feeding Survey, published by the UK government in 2026, found that 16% of mothers reported that their baby had been diagnosed with tongue-tie by a healthcare professional or infant feeding specialist. Among babies whose tongue-tie was reported to cause feeding or other problems, 75% had undergone a frenotomy, with about two-thirds of those procedures taking place through the NHS.
At the same time, the evidence for long-term benefits remains uncertain. The British FROSTTIE randomised trial found no measurable difference in breastfeeding rates at three months between babies assigned to immediate frenotomy plus breastfeeding support and those initially assigned to breastfeeding support alone. However, the study recruited only 169 of the planned 870 participants and had substantial crossover between groups, meaning the researchers said it could not provide a definitive answer.
This uncertainty explains why the debate increasingly concerns not whether tongue-tie can ever cause feeding problems, but how to identify the smaller group of babies for whom surgery is likely to provide a meaningful benefit.
The forthcoming Finnish results could therefore have implications beyond Finland. With procedures becoming more frequent in several countries while diagnostic criteria remain inconsistent, better evidence could help Nordic and European healthcare systems distinguish between cases where frenotomy is clinically justified and those where breastfeeding support or further assessment should come first.
