AbstractAimWe evaluated what determined breastfeeding problems in a non‐selected mother‐infant cohort, with special reference to tongue‐tie and improvements in breastfeeding following frenulotomy.MethodsThis 2014‐2015 prospective, observational study was carried out in a tertiary level maternity unit affiliated to the University of Freiburg, Germany, using a breastfeeding questionnaire, standardised breastfeeding scores and the Assessment Tool For Lingual Frenulum Function (ATLFF). The standard intervention was breastfeeding support, a frenulotomy for tongue‐tie was performed if necessary. All cases of breastfeeding problems and, or tongue‐tie, were followed up by telephone 2.5 weeks after birth.ResultsWe enrolled 776 newborn‐mother dyads: 345 had breastfeeding problems, 116 had a tongue‐tie and 30 underwent a frenulotomy. In the multivariate analysis, severe breastfeeding problems were more frequent in newborn infants with tongue‐tie, with an odds ratio (OR) of 2.6 (P= 0.014). Other risk factors were: no breastfeeding experience (OR 4.4, P = 0.001), low birth weight (OR 2.9, P = 0.001), prematurity (OR 3.6, P = 0.000) and Caesarean section (OR 1.6, P = 0.023). There was a significant reduction in breastfeeding problems after frenulotomy (P = 0.01).ConclusionTongue‐tie had a significant impact on breastfeeding and so did low birth weights and prematurity. Frenulotomy proved helpful when breastfeeding problems were reported.