Fructosamine in relation to maternofetal glucose and insulin homeostasis in gestational diabetes.

The problem in screening for gestational diabetes is recognizing fetuses endangered by hyperinsulinism. 21.8% of patients with gestational diabetes (defined as a glucose peak exceeding 160 mg/dl after an oral glucose load of 1 g per kg body weight) develop fetal hyperinsulinism. Thus, is indicated by an elevated amniotic fluid insulin (AFI) concentration and requires insulin treatment. Since fetal hyperinsulinism can be neither predicted nor ruled out by single parameters of maternal metabolism, every patient with gestational diabetes had to undergo amniocentesis for amniotic fluid analysis. In 110 gestational diabetics and 822 controls, fetal hyperinsulinism was predicted by the combination of the oGTT (greater than or equal to 160 mg/dl) and maternal serum fructosamine (greater than or equal to 2.6 mmol/l) with a sensitivity of 95.8% and a specificity of 91.8%. Thus, 73% of gestational diabetics need not undergo amniocentesis. With a sensitivity of 20.8%, the combination of the oGTT and HbA1c is not useful in identifying hyperinsulinemic fetuses.