Carbohydrate Intake and Oral Glucose Tolerance Test Results in the Postpartum Period

Abstract

Abstract Context The American Diabetes Association (ADA) recommends a 3-day preparatory diet prior to a diagnostic oral glucose tolerance test (OGTT), a test often recommended in postpartum individuals with a history of gestational diabetes (GDM). Objective Evaluate the relationship between carbohydrate intake and OGTT glucose in 2 cohorts of postpartum individuals. Methods We performed analyses of postpartum individuals from 2 prospective studies with recent GDM (Balance after Baby Intervention, BABI, n = 177) or risk factors for GDM (Study of Pregnancy Regulation of INsulin and Glucose, SPRING, n = 104) .We measured carbohydrate intake using 24-hour dietary recalls (SPRING) or Food Frequency Questionnaire (BABI) and performed 2-hour 75-g OGTTs. The main outcome measure was 120-minute post-OGTT glucose. Results There was no relationship between carbohydrate intake and 120-minute post-OGTT glucose level in either study population (SPRING: β = 0.03, [−5.5, 5.5] mg/dL, P = .99; BABI: β = −3.1, [−9.5, 3.4] mg/dL, P = .35). Adding breastfeeding status to the model did not change results (SPRING β = −0.14, [−5.7, 5.5] mg/dL, P = .95; BABI β = −3.9, [−10.4, 2.7] mg/dL, P = .25). There was, however, an inverse relationship between glycemic index and 120-minute post OGTT glucose (BABI: β = −1.1, [−2.2, −0.03] mg/dL, P = .04). Conclusion Carbohydrate intake is not associated with post-OGTT glucose levels among postpartum individuals. Dietary preparation prior to the OGTT may not be necessary in this population.