This HbA1c Threshold Can ID Diabetes in Early Pregnancy
(HealthDay News) — An HbA1c threshold of ≥5.9% can identify all women with gestational diabetes in early pregnancy, according to a study published online September 4 in Diabetes Care.
Ruth C.E. Hughes, MBBCh, from the University of Otago in New Zealand, and colleagues analyzed data from a group of women who completed an early oral glucose tolerance test (OGTT) and HbA1c tests. Pregnancy outcome data were also assessed.
In 16,122 women, HbA1c was measured at a median of 47 days' gestation. Twenty-three percent of those offered (974 women) took an early OGTT, and in this subset all 15 cases of diabetes were identified with HbA1c ≥5.9%. For gestational diabetes mellitus before 20 weeks this threshold was 98.4% specific (positive predictive value, 52.9%). Excluding the women referred for gestational diabetes, women with HbA1c of 5.9–6.4% had poorer pregnancy outcomes than those with HbA1c <5.9% (8,174 women): relative risk of major congenital anomaly was 2.67; pre-eclampsia, 2.42; shoulder dystocia, 2.47; and perinatal death, 3.96.
"HbA1c measurements were readily performed in contrast to the low uptake of early OGTTs," the authors write.