Hormonal counterregulation of hypoglycaemia in IDDM patients during and after pregnancy

ABSTRACT

An increased frequency of hypoglycaemic events is commonly observed during pregnancy in intensively treated IDDM patients. It has been speculated upon whether this is due in part to impairment of the hormonal counterregulation. The main aim of this study was to clarify if the hormonal response to hypoglycaemia is modified during pregnancy. Therefore we assessed plasma levels of catecholamines, GH and cortisol as well as subjective symptoms and cognitive functions during a hyperinsulinaemic, hypoglycaemic clamp in the third trimester of pregnancy and 6-12 months after delivery. Venous samples for the analysis of hormones and free insulin were taken every 15 minutes and symptoms of hypoglycaemia were recorded on a visual analogue scale at 30-min intervals. Cognitive functions were studied by a psychological test system at normoglycaemia and at hypoglycaemia. The Wilcoxon signed rank test was used for statistical calcuations. The levels of noradrenaline (mean at hypoglycaemia pregnant 2.30, and non-pregnant 2.44 nmol/l, n.s.) increased the same way on the two occasions, while the adrenaline response was some what higher in the pregnant state (2.09 vs 1.66 nmol/l non-pregnant, p<0.05). The cortisol increase was faster and more pronounced during pregnancy (mean increase 327 vs 130 nmol/non-pregnant, p<0.0001) while the increase in GH was higher in the non-pregnant state (mean increase 23.6 vs 8.7 æg/l pregnant, P<0.0001). We conclude that the present study does not, with the exception of GH, give evidence that pregnancy per se diminishes the counterregulatory hormones response (AU)