AimTo evaluate the effectiveness of a breastfeeding support programme on reducing infant formula use and to investigate indications for formula in newborn infants in Sweden.MethodsA quasi‐experimental study design was carried out. It included 255 mother‐infant pairs in a control group, who received standard care and 254 pairs in an intervention group, who took part in a breastfeeding support programme. Data were collected by reviewing patient records from two regional hospitals in Uppsala and Gotland and recruitment took place between 2017 and 2019.ResultsMedian age of mothers were 31 years (range 20–49) and median gestational age of infants were 39 + 6 weeks/days (range 37 + 0 to 42 + 4). The intervention did not reduce infant formula use. In total, 87/507 (17%) of the infants received formula. Among children receiving formula 30/87 (34%) had a medical indication, whereas 57/87 (66%) had no medical indication. Main reasons for medically indicated formula use were hypoglycaemia, 13/30 (43%), and weight loss, 13/30 (43%). Main reasons for non‐medical use were mothers'/parents' wishes, 25/57 (44%) and infants' dissatisfaction, 11/57 (19%).ConclusionContinued efforts are needed to develop effective breastfeeding interventions with increased focus on infant formula reduction.