SummaryThe main features of the infant of a diabetic mother are reviewed in relation to the recent physiopathological data that may result in these anomalies. The PEDIiRSEN’s hypothesis suggests the following sequence: maternal hyperglycaemia—fetal hyperglycaemia—fetal hyperinsulinism. Whereas congenital defects seem due mainly to hyperglycae mia in the early embryonic period, macrosomia and respiratory distress syndrome arc probably directly induced by the fetal hyperinsulinism. as is the neonatal hypoglycaemia. However, concerning the evoking mechanism of the latter, there is also evidence of an impaired glucagon and catecholamine release. Polycythemia appears related to the drop in arterial oxygen content, which is most likely secon dary to an increased consumption in the fetal organism. Finally fetal or neonatal myocardial function can be impaired in a number of cases.