705: Value of A1c in gestational diabetes

Abstract

Hemoglobin A1c (A1c) is frequently checked in gestational diabetes (GDM), although its correlation with outcomes in GDM is unclear. We hypothesized that women with GDM and an elevated A1c at 14-20 or 24-28wks have worse perinatal outcomes when compared to their GDM counterparts with normal A1c. We also hypothesized that in GDM, A1c change (ΔA1c) from 14-20wks to 24-28wks is associated with adverse perinatal outcomes. Secondary analysis of a multicenter randomized controlled trial assessing early (14-20wks) vs. routine (24-28wks) screening for GDM in obese women. A1c was obtained at 14-20 (A1c14) and 24-28 weeks (A1c24). ΔA1c was defined as A1c24-A1c14. The primary outcome was a composite of adverse perinatal outcomes including macrosomia, primary cesarean delivery, pregnancy-induced hypertension, shoulder dystocia, neonatal hypoglycemia, or hyperbilirubinemia. Receiver operator characteristics curve (ROC) was used to visually assess the association of A1c14, A1c24, and ΔA1c with the composite outcome. The Liu method was used to select an optimal cutoff, and the incidence of the composite outcome was compared between those above and below the selected cutoff. Of 125 women with GDM, 103 (82%) had A1c14, and 93 (74%) had A1c14 and A1c24. The ROC curve for A1c14 had an area under the curve of 0.63, 95% CI 0.5-0.7. At the Liu cutoff of ≥5.5%, the composite perinatal outcome was not significantly increased, although hyperbilirubinemia was increased. The AUC for A1c24 was also 0.63, 95% CI 0.5-0.7 and an A1c24 above the cutoff (≥5.65%) was not associated with adverse perinatal outcomes. The AUC for ΔA1c was 0.54, 95% CI 0.4-0.6, with a cutoff of ≥0. Again, the composite perinatal outcome was not significantly increased above the Liu cutoff, but preterm delivery < 37 weeks was. A single A1c in GDM is not associated with a composite perinatal adverse outcome, but an A1c that increases between 14-20 and 24-28wks may be associated with an increase in preterm delivery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)