Longitudinal assessment of glycosylated blood protein concentrations in normal pregnancy and gestational diabetes.

Longitudinal changes in glycosylated hemoglobin concentration (GlyHb) and glycosylated serum protein concentration (GSP) in both normal pregnancy and pregnancy complicated by gestational diabetes were determined using affinity chromatography, a method in which nonenzymatically glycosylated proteins are specifically measured. At 7-10 wk gestation, GlyHb in women who developed diabetes (N = 21) was higher than GlyHb in normal women (N = 49) (6.7 +/- 0.2% versus 5.7 +/- 0.2%, respectively, P less than 0.001) and remained elevated throughout gestation. In normal pregnancy, GlyHb decreased to a nadir at 23-26 wk and returned to baseline concentration by 31-34 wk. In gestational diabetes, there was an initial increase in GlyHb to 7.1 +/- 0.5% at 11-14 wk followed by a steady decrease. At 7-10 wk, GSP in women who developed diabetes was not elevated compared with normal concentration, although at 11-14 wk there was significant difference between the two groups (P less than 0.02). In normal women, GSP remained constant throughout gestation. In gestational diabetes, GSP decreased to early pregnancy values (P less than 0.02). Glycosylated blood proteins were elevated in early gestation in women who developed gestational diabetes and may have predictive value in identifying women who will develop diabetes in pregnancy.