 The evolution of the composition of the intestinal microbiota will be evaluated in both groups at 7d, 30d, 4-6 months prior to weaning, 12,18,24,30,36, 42, 48, 54 and 60 months. The bacterial composition of stool will also be analyzed in a sub-sample of children developing active CD and in non-CD controls. All patients who develop CD will continue in the study. 