Cardiac growth in fetuses of diabetic mothers with good metabolic control

To evaluate cardiac growth in fetuses of those diabetic mothers with good metabolic control, we examined M-mode echocardiographic measurements obtained from 24 fetuses of diabetic mothers (FODM) and compared these with measurements from 31 normal fetuses of similar gestational age. Fetuses were grouped into three gestational periods: 20 to 26 weeks, 27 to 33 weeks, and 34 to 40 weeks. The mothers were believed to have good metabolic control on the basis of mean daily glucose profiles and glycosylated hemoglobin A (HbA_1c) values of approximately 110 mg/dl (610 μmol/L) and 7.5%, respectively, before fetal scanning, and estimated fetal weight similar to that of normal fetuses during all three gestational periods. Both FODM and normal fetuses had significant increases in M-mode measurements from period 1 to period 3, but in FODM, cardiac hypertrophy developed by late gestation (period 3). This involved the interventricular septum (6.1±0.7 vs 4.9±0.3 mm, p<0.05), right ventricular free wall (5.7±0.8 vs 3.2±0.3 mm, p<0.01), and left ventricular free wall (6.4±0.6 vs 3.3±0.4 mm p<0.01). The interventricular septum/right ventricular free wall ratio was similar, whereas the interventricular septum/left ventricular free wall ratio in FODM was smaller by period 3 (1.0±0.1 vs 1.6±0.1, p<0.05). The right ventricular diastolic dimension was similar, but the left ventricular diastolic dimension was significantly smaller in FODM during periods 2 and 3 (8.2±1.2 vs 12.2±0.7 mm, p<0.05). Strict metabolic control did not prevent FODM from having abnormal cardiac growth. We conclude that good metabolic control results in normal estimated fetal weight but that FODM remain at risk for mild global cardiac hypertrophy and altered diastolic dimensions.