We read with interest the article ‘Hospitalisation for bronchiolitis in infants is more common after elective caesarean delivery’.1 A previous study has reported that asthma before 3 years of age is associated with planned and emergency caesareans, (with higher risk for emergency caesarean).2 The suggested pathway is that gut microflora play a part in the development of the infant immune system, and children born by caesarean have atypical microflora colonisation compared to those born vaginally.3 Surprisingly, Moore et al found that only planned caesarean had a statistically significant risk for bronchiolitis. This they attributed to differences in cytokine environment rather than the physiologic consequences of exposure to labour.4 We decided to replicate the study in another population, …