The outcome of diabetic pregnancies: a prospective study.

In a large prospective study of pregnancy the perinatal mortality rate was 141/1000 births for diabetic gestations in which the onset of labour was spontaneous, 33/1000 for diabetic gestations in which labour was induced or the infant delivered by Caesarean section and 34/1000 for the non-diabetics. Forty per cent of the perinatal mortality excess in the diabetics was due to the consequences of maternal vascular lesions, i.e. large placental infarcts and marked retardation of placental growth. Seventeen per cent of the perinatal mortality excess was related to maternal acidosis or to insulin shock, 12% to severe congenital anomalies, 12% to the complications of Caesarean sections and the remainder to other disorders. Mothers with diabetes mellitus had more than twice the frequency of atheromata, fibrinoid change and thrombi in decidual arteries as non-diabetic mothers. Histological grading revealed that overweight newborns of diabetic mothers had immature lungs by comparison with the lungs of normally grown infants of diabetic mothers and infants of non-diabetic mothers. Low IQ values and an excess of neurological abnormalities in children of diabetic mothers who were ketotic during pregnancy were found to be due to amniotic fluid bacterial infections and their complications rather than to the maternal ketosis.