Diabetes in pregnancy, Northwestern University series (1977-1981). I. Prospective study of anomalies in offspring of mothers with diabetes mellitus.

Offspring of mothers with diabetes mellitus were examined prospectively with the use of a detailed checklist. Diabetic women were usually identified in the late first or early second trimester and thereafter rigorously managed in hopes of achieving euglycemia. The frequency of infants with major anomalies was higher (9/106, 8.5%) in White Classes B to F than in either the general population or in a small group of concurrently gathered control subjects (1/41, 2.4%). The frequency of anomalies in Class A diabetes was 3/76 (3.9%), a rate that may or may not be increased. Of the 12 major anomalies observed in diabetic offspring, six involved the heart and three involved the skeletal system. No pattern of minor anomalies appeared to exist. Limited data failed to reveal a specific HLA type that conferred increased risk for anomalies, and chromosomal abnormalities were not increased in frequency. If hyperglycemia is indeed the mechanism responsible for anomalies in offspring of mothers with diabetes mellitus, our observations suggest that rates will be reduced only by achieving optimal control in the first trimester.