Relationship Between 1,5 Anhydroglucitol, Glycemia, and Breastfeeding During Pregnancy and Postpartum: A Pilot Study

Background: Assessments for hyperglycemia are vital to pregnancy and postpartum (PP) care, but gold-standard oral glucose tolerance tests (OGTTs) are burdensome. We examined changes in 1,5 anhydroglucitol (1,5AG) levels during gestation and PP and assessed for associations with other measures of glycemia.

Study design: Pregnant participants (n = 50) in the Study of Pregnancy Regulation of Insulin and Glucose cohort underwent OGTTs at a mean of 13 weeks ([visit 1 (V1)] and 26 weeks [visit 2 (V2)] of gestation and PP. Nonpregnant controls had a single OGTT. 1,5AG was measured using frozen plasma samples. Changes in 1,5AG across pregnancy were assessed with longitudinal mixed effects linear models. We assessed relationships between 1,5AG and glycemia at each timepoint using Spearman correlations and linear regression models. To determine the relationship of 1,5AG with breastfeeding (BF) status, stratified analyses were performed.

Results: 1,5AG decreased from V1 to V2 (β = -3.6 μg/mL, P < .001) and remained low PP compared to V1 (β = -1.4 μg/mL, P = .018). Comparisons between pregnant/PP and nonpregnant participants revealed lower 1,5AG values at all timepoints (V1 β = -9.9μg/mL, P < .001; V2 β = -14.0 μg/mL, P < .001, PP β = -11.4μg/mL, P < .001). There was no association between 1,5AG and glycemia. Compared to those exclusively feeding formula, 1,5AG levels were significantly lower in exclusively BF women (β = -8.8 μg/mL, P < .001) and intermediate in women feeding both breastmilk and formula (β = -6.1μg/mL, P < .001), independent of glycemia.

Conclusion: 1,5AG decreases during gestation and remains low PP. Breastfeeding is associated with lower 1,5AG levels, indicating plausible excretion into breastmilk. 1,5AG is unlikely to be useful in assessing glycemia in pregnant or PP women.