Aspects of hypoglycaemia in newborns of diabetic mothers and in children with Type 1 diabetes

Abstract: The occurrence and possible causal factors of macrosomia and postnatal hypoglycaemia were investigated in infants of diabetic mothers. Acute neurophysiological effects, the long-term nemodevelopmental outcome, and the use of glucagon in prevention and treatment of hypoglycaemia, were also studied in children with insulin-dependent diabetes mellitus (IDDM) and infants of diabetic mothers.Infants born 1986-1993 of diabetic mothers, and children 7-12 years of age with !DD M, were investigated at Orebro Medical Centre Hospital. Macrosomia (birth weight>+ 2SD, adjusted for gender and gestational age) occurred in 27% of infants of mothers with gestational diabetes mellitus (GDM) and in 30% of those of mothers with !DD M. Postnatal hypoglycaemia (B-glucose < 1.5 rnmol/l) was observed in 38% of the infants. A highly positive con-elation was found between cord plasma insulin growth factor-! (IGF-l) and relative birth weight ratios in infants of diabetic mothers (r ~ 0.64, p < 0.0007), suggesting a role for IGF-I in the development of macrosomia in diabetic pregnancy. Early postnatal hypoglycaemia was related to cord serum C-peptide levels, supporting the theory of foetal hyperinsulinaemia as the most important pathogenetic factor. Maternal glucose concentration at labour was also related to cord C-peptide concentration, indicating that maternal glucose regulation close to delivery is important for postnatal glucose regulation in the infants. At follow-up at the age of 8 years, children with neonatal hypoglycaemia of diabetic mothers had a lower total developmental score than control children. More difficulties at an :MBD screening test and more behavioural problems were also noted in this group. At quantitative EEG analysis, children with neonatal hypoglycaemia of diabetic mothers more often showed a pattern similar to that in children with attention deficit hyperactivity disorders/attention deficit disorders compared with those who were "normoglycaemic" in the neonatal period.To treat neonatal hypoglycaemia, an injection of subcutaneous glucagon, 20 Jlg/kg, was given 3 hours postnatally in addition to early oral feeding. This caused a significant rise in blood glucose concentration lasting for up to 60 min (p < 0.01), compared to oral feeding alone, without major side-effects. However, the duration of the hyperglycaemic effect was too brief to eliminate the need for additional intravenous glucose infusion.IDDM children, with a short duration of disease and good metabolic control, showed no progressive neurophysiological effects, as measured by brainstem auditory evoked potentials (BAEP), during short-term induced hypoglycaemia (1.7 mmolll). This suggests that children with IDDM better adapt to low blood glucose levels than adult diabetic patients. Nor did the IDDM children show permanent BAEP changes during normoglycaemia, compared with a control group of healthy children of the same age.In treatment of hypoglycaemia in IDDM children intranasal administration of glucagon (1 mg) and subcutaneous glucagon injection (0.5 mg) had similar hyperglycaemic effects as observed for up to 30 minutes. Fewer side-effects, including nausea and vomiting, and only minor nasal irritation were reported after intranasal glucagon administration.