HORMONAL, METABOLIC, AND CIRCULATORY RESPONSES TO INSULIN-INDUCED HYPOGLYCEMIA IN PREGNANT AND NONPREGNANT WOMEN WITH INSULIN-DEPENDENT DIABETES

Strict blood glucose control of pregnant women with insulin-dependent diabetes is associated with increased risk of hypoglycemia. The hormon al and circulatory responses to an acute episode of insulin-induced hy poglycemia were studied in eight pregestational and one gestational di abetic women during the last trimester of pregnancy and 8 to 12 weeks postpartum. Following an overnight fast, insulin was injected intraven ously (0.1 to 0.2 IU insulin/kg). Blood samples were taken at -15, 0, 15, 30, 40, 60, 90, and 120 minutes for analyses of metabolites (gluco se, nonesterified fatty acid (NEFA), glycerol, 3-hydroxybutyrate) and counterregulatory hormones (epinephrine, norepinephrine, glucagon, and cortisol). Placental scintigraphy (indium-113m) was performed in five pregnant patients before and during hypoglycemia. Both during pregnan cy and postpartum, blood glucose decreased to the same low level (3.2 mmol/L) concomitantly with significant decreases in NEFA, glycerol, an d 3-hydroxybutyrate. Epinephrine and norepinephrine showed significant and similar increases on both occasions in relation to hypoglycemia, although there was no response in glucagon and cortisol concentrations . Maternal heart rate was significantly higher in the pregnant compare d with the nonpregnant state and increased significantly in both group s in response to hypoglycemia. Placental blood flow showed no consiste nt changes and was unrelated to the glucose and catecholamine response s. Fetal heart rate remained unchanged. Thus, it seems as if hormonal and circulatory responses to acute hypoglycemia are not altered in dia betic women during pregnancy.