Circulatory adaptation in newborn infants of strictly controlled diabetic mothers.

Possible relations between neonatal circulatory function and maternal diabetic control were investigated in 22 infants of strictly controlled diabetic mothers during the first 2 days after birth. Eleven infants were delivered vaginally (V) and 11 infants by elective cesarean section (S). Maternal diabetes was more severe in the latter group. Half of the infants had one or more episodes of neonatal morbidity although none presented symptomatic hypoglycemia. Plasma glucose FFA and C-peptide were measured at birth and 3-6 hours later together with skinfold thickness; heart size was determined by X-ray at 24-28 hours; stroke volume and cardiac output were repeatedly determined by transthoracic impedance and ECG. C-peptide at birth was higher in group S than in V. C-peptide in both groups were neither related to glucose or FFA nor to birthweight or skinfold thickness. Infants with neonatal complications including cardiomegaly had the highest C-peptide values. Skinfold was positively correlated to maternal pregnancy glucose level, birthweight percentile and infant heart volume. Mean values for stroke volume and cardiac output were similar in both groups and not different from normal controls when related to body weight. Heart volume and stroke volume were significantly related. ECG abnormalities were seen in 6 infants who showed cardiomegaly on X-ray. We suggest that the present finding of an association between elevated C-peptide concentration at birth and the occurrence of neonatal complications including cardiomegaly and ECG abnormalities could be the consequence of functional hyperinsulinism and that the cardiomegaly is of adaptive type.