Maternal diabetic control and hypertrophic cardiomyopathy in infants of diabetic mothers.

Hypertrophic cardiomyopathy has been well documented in infants of diabetic mothers (IDMs). If this asymmetric septal enlargement is an anabolic result of fetal hyperinsulinemia triggered by maternal hyperglycemia during the third trimester, maternal glycosylated hemoglobin (HbA1) levels, an indicator of glycemic control, should then correlate positively at delivery with newborn ventricular septal thickness. In this study of 20 infants of well-controlled diabetic mothers, no relationship was observed between echocardiographic evidence of hypertrophic cardiomyopathy and maternal HbA1 levels. Seven babies (35%) exhibited exaggerated septal thickening, but none had cardiac-specific symptoms. Although 60 percent of the IDMs were large for gestational age and 45 percent demonstrated neonatal hypoglycemia, neither of these complications correlated with maternal HbA1. In this group of babies of well-controlled diabetic women, echocardiographic indicators of cardiomyopathy were common, but clinical evidence of cardiac embarrassment was not observed. Moreover, these data do not support third trimester maternal hyperglycemia as instrumental in the etiology of cardiomyopathy and other complications of IDMs.