The effect of modern antepartum and intrapartum fetal monitoring techniques on the outcome of the pregnancy complicated with diabetes was studied by comparing the perinatal mortality of 2 groups of patients whose management differed primarily by the use of these tests. The perinatal death rate was halved to 9.2%, and when corrected for major congenital defects and referred fetal deaths it was 5.3%. Modern fetal diagnostic tests clearly add a degree of objectivity in the management of the diabetic pregnancy not previously available.