Cardiac and extracardiac complications in infants of diabetic mothers and their relation to parameters of carbohydrate metabolism

Abstract

Despite the current improvement of diabetes care in pregnancy, neonatal complications are still more frequent than in the general population. Even in fetuses of well controlled diabetic mothers, myocardial hypertrophy can be demonstrated although it is not related to maternal metabolic control. The objective of this study was to determine perinatal complications and the course of myocardial hypertrophy in newborns who had been prenatally monitored and to relate the findings to neonatal parameters of carbohydrate metabolism. Perinatal complications and echocardiographic evidence of myocardial hypertrophy were determined in 104 neonates of closely followed diabetic mothers. Cord blood was obtained for determination of insulin, C-peptide and glycosylated fetal haemoglobin (HbF_1c). In cases of myocardial hypertrophy, the echocardiographic examinations were repeated until normalisation of the myocardial wall thickness. The most striking finding was myocardial hypertrophy in 25% of the 104 neonates, which predominantly involved the interventricular septum. This is in contrast to the prenatal symmetrical hypertrophy of the ventricular walls and may be explained by perinatal changings of ventricular geometry. There was no sign of outflow tract obstruction, and myocardial hypertrophy resolved within 6 months. Insulin and C-peptide were elevated in the majority of the newborns, whereas HbF_1c was significantly decreased. Neither the maternal type of diabetes nor neonatal metabolic data were related to the somatic findings.

Conclusion Myocardial hypertrophy still occurs in infants of diabetic mothers despite their good met abolic control reflected by the decreased fraction of glycosylated fetal hemoglobin which points to low fetal blood sugar levels during the last intra-uterine weeks.