953-P: Glycated Albumin Is Not an Accurate Marker of Glycemia in Pregnancy or Postpartum Free

Objective: Assessments for diabetes are vital to pregnancy and postpartum (PP) care, but screening, conducted with oral glucose tolerance tests (OGTTs), is cumbersome. Outside of pregnancy, percent glycated albumin (%GAlb) reflects average glycemia over a period of weeks. %GAlb may not be subject to the same limitations as hemoglobin A1c in pregnancy, as it does not rely on stable red blood cell kinetics. We studied %GAlb as a potential glycemic marker during gestation and PP.

Study Design: Pregnant women (N=50) in the Study of Pregnancy Regulation of Insulin and Glucose cohort underwent 75g OGTTs at a mean of 13 weeks (SD 1.6, V1) and 26 weeks (SD 1.4, V2) of gestation and 11 weeks (SD 4.9) PP. Non-pregnant controls had a single OGTT. We measured GAlb on frozen plasma samples.

Results: Serum total GAlb and total albumin decreased from V1 to V2 and increased PP to levels higher than at V1. %GAlb declined between V1 and V2 (β= -0.64 95% CI [-0.8, -0.4] p<0.001) and remained stable between V2 and PP (β= -0.04 [-0.3, 0.2] p=0.66). Age-adjusted comparisons to non-pregnant controls showed that %GAlb values were similar to controls at V1 (β=0.05 [-0.5, 0.6] p=0.84), and were lower at V2 (β= -0.53 [-1.1, 0.0] p=0.05) and PP (β= -0.62 [-1.1, -0.1] p=0.02). Neither glucose levels nor hemoglobin A1c were associated with %GAlb at V1, V2, or PP. BMI was inversely related to %GAlb in pregnancy (V1: rho= -0.5, p=0.0001; V2 rho= -0.4, p=0.006), but not PP (rho= -0.2, p=0.31). BMI was higher at both V2 (β=2.05 [1.5, 2.6] p<0.001) and PP (β=0.65 [0.1, 1.2] p=0.01 compared to V1. However, BMI-adjusted longitudinal changes in %GAlb were similar to those in unadjusted analyses. Adjustment for BMI also did not reveal associations between %GAlb and glucose levels or A1c.

Conclusions: %GAlb decreases during gestation and remains decreased PP, despite a return of total albumin and total GAlb to baseline. Given the lack of correlation with OGTT glucose levels or hemoglobin A1c, %GAlb is unlikely to be useful in assessing glycemia in pregnant or PP women.