Glycosylated Hemoglobin: A Sensitive Indicator of Gestational Diabetes

Abstract

Previous studies suggested that the assessment of hemoglobin A1 (HbA1) concentration was a poor indicator of diabetes in pregnancy. However, HbA1 was measured by ion exchange chromatography, which is subject to spurious alterations. To reevaluate the use of glycosylated hemoglobin concentration (GlyHb) as an indicator of gestational diabetes, 64 women at 10 to 15 weeks' gestation were studied by measuring GlyHb by a specific affinity chromatography assay, and blood glucose concentration was determined one hour post a 50-g oral glucose load. Gestational diabetes developed in 15 women in whom GlyHb (7.4 +/- 0.2%) was greater than in normal pregnant women (5.7 +/- 0.1%, P less than .001). If a GlyHb of 6.3% were chosen as the threshold for diagnostic evaluation for diabetes, only 6.7% of the gestational diabetics would have missed diagnosis. Of normal women, 14.2% would have been subjected to glucose tolerance test. GlyHb elevation was associated with the birth of infants large for gestational age. The assessment of GlyHb by affinity chromatography between 10 and 15 weeks' gestation may be a sensitive predictor of patients who will develop gestational diabetes.

Antepartum A1C, maternal diabetes outcomes, and selected offspring outcomes: an epidemiological review

“…Among women with diabetes in pregnancy, A1C at time of GDM diagnosis does appear to be associated with birthweight, 44,47,48 macrosomia, 38 and LGA 39,40 . In a retrospective cohort study of 357 women with GDM using the WHO criteria, Zawiejska et al 44 .…”

Glycosylated Hemoglobins in Pregnant Women with Normal and Abnormal Glucose Tolerance

“…In contrast, Mor ris et al [10] in their study at 10-15 weeks of gestation concluded that HbAi by affinity chromatography may be a sensitive predictor of patients who will develop gesta tional diabetes. With a 1 SD threshold value, only 6.7% of the gestational diabetics would have missed diagnosis while 14.2% of the normal women would have been sub jected to further testing.…”

“…In a prenatal screening test for carbohydrate intolerance, Cousins et al [9] found that the 1-hour glucose challenge test (GCT) had greater specificity, sensitivity and predictive value for a positive diagnosis than the HbA] test. In contrast, Morris et al [10] reported that HbAi, determined by affinity chroma tography, may be used as a sensitive predictor of patients who will develop gestational diabetes during early preg nancy (10-15 weeks). Most reported studies were performed on Western populations.…”

“…However, conflicting results have been reported [6][7][8][9][10], Most investigators have found that HbA| concentrations are ineffective in detecting glucose intoler ance [6][7][8]. Artal et al [8] compared HbAi values in 82 women in the third trimester with a 100-gram glucose tol erance test (GTT).…”

The utility of a single test to identify women at risk for gestational diabetes

“…Conclusions differ regarding the use of hemoglobin A 1c for such a test. In three studies, at threshold values selected to detect from 67% to 88% of gestational diabetic patients, the false-positive rates ranged from 25% to 65% [51][52][53]. The latter figures represent the proportion of the entire population who would require glucose tolerance testing because they exceed the designated hemoglobin A 1c value but who would be found not to have GDM.…”