Obstetric history of diabetics: its relevance to the aetiology of diabetes.

The birth weights of infants born to patients with insulin-dependent diabetes (IDD) and insulin-independent diabetes (IID) before the disease was diagnosed were compared. An appreciable excess of infants above the 90th centile for weight was found, the proportions being 27% of infants born to mothers with IDD and 30% of those born to mothers with IID. These findings suggest that many patients with both types of diabetes have a prolonged period of metabolic abnormality before overt symptoms of diabetes arise and that the apparent acute onset of the disease in patients who are insulin dependent is illusory.