OBJECTIVE. Our aim was to determine the echocardiographic incidence of asymmetric septal hypertrophy in large for gestational age infants born to diabetic mothers and to compare such incidence to large for gestational infants born to mothers without diabetes. Furthermore, it is our goal to describe the outcome and course of this condition.

STUDY DESIGN. Observational, longitudinal, comparative and prospective.

METHODS. During one year all infants born in our institution who were classified as large for gestational age, whether the mother was diabetic or not, and all infants of diabetic mothers were included in this study. A 2-D Doppler Ecocardiography was performed in each infant within the first 24 hs of extra-uterine life. Infants with abnormal echocardiographic results at birth were followed-up clinically and echocardiograms were repeated at 2 and at 6 months of age.

RESULTS: A total of 85 infants of diabetic mothers and 80 infants large for gestational age of non-diabetic mothers were studied. Asymmetric septal hypertrophy was present in 38.8% of the initial echocardiograms in infants of diabetic mothers. In large infants of non-diabetic mothers the incidence was 7.5%. The difference was statistically different (p <0.01). The severity of the hypertrophy and the association with clinically significant cardiorespiratory problems during the neonatal period were variable. Furthermore, we did not find a relationship between the success of metabolic diabetic control during pregnancy with the incidence nor with the clinical severity of the septal hypertrophy. On follow up echocardiograms the condition was not yet completely resolved in >10% by 6 months of age.

DISCUSSION. Asymmetrical septal hypertrophy is a common finding in infants of diabetic mothers, with an echocardiographic incidence of 38.8% in this study. The condition occurs independently of maternal diabetic control. In addition, the association with long term cardiovascular disease in these infants remains to be defined.