USE OF GLYCOSYLATED HEMOGLOBIN AS A SCREEN FOR MACROSOMIA IN GESTATIONAL DIABETES

Glycosylated Hb and blood sugar levels in the fasting state and 2 h after oral 100 g glucose load were measured in 180 patients. Glycosylated Hb was measured by cation exchange column chromatography, and blood sugar was measured by hexokinase reaction. Patients with an elevated postprandial and or fasting blood sugar level (positive screen) subsequently underwent 3-h glucose tolerance test. The mean value of glycosylated Hb in patients with a negative screen and normal Hb was 6.17 .+-. 0.16%; and the value for glycosylated Hb in patients with class A diabetes and normal Hb electrophoresis was 6.85 .+-. 0.73% (P < 0.001). A glycosylated Hb value > 6.78 (mean + 1 SD) was considered elevated. Glycosylated Hb values were considered elevated. Glycosylated Hb values were elevated in 21 of 33 patients with gestational diabetes and in 27 of 147 patients with normal blood sugar levels. The sensitivity and specificity of glycosylated Hb for the diagnosis of gestational diabetes were 63.6 and 81.6%, respecticely. Of patients with an initially elevated glycosylated Hb value, 50% delivered macrosomic infants, whereas no patient with a normal glycosylated Hb value had a macrosomic infant. An elevated glycosylated Hb value may alert the obstetrician of a potentially elevated mean blood sugar level and may warrant aggressive management of gestational diabetes.