Intrapartum azithromycin is being evaluated as a potential intervention for preventing maternal sepsis and mortality. This study evaluated the effect of intrapartum azithromycin on the development of the child gut microbiome over the first 3 years of life. The study used samples from healthy Gambian children who were recruited in the PregnAnZI-2 trial (ClinicalTrials.org NCT03199547). PregnAnZI-2 was a large clinical trial conducted in The Gambia and Burkina Faso to assess the effect of 2g oral azithromycin given to women during labour, on neonatal sepsis and mortality.