Relationship between carbohydrate intake and oral glucose tolerance test results among pregnant women.

ABSTRACT

AIMS: Evaluate the relationship between self-reported carbohydrate intake and oral glucose tolerance test (OGTT) results in pregnancy. METHODS: We measured carbohydrate intake using 24-hour dietary recall and performed a 2-hour 75-gram OGTT in 95 pregnant women with risk factors for gestational diabetes (GDM) at a median of 26 weeks' gestation. We tested for associations between carbohydrate intake in the 24 hours preceding the OGTT and 60-minute OGTT glucose, glucose at other timepoints, and glucose area under the curve (AUC) using linear regression, with adjustment for potential confounders. RESULTS: We observed an inverse linear relationship between carbohydrate intake (median 237 grams [interquartile range 196, 303]) and 60-minute OGTT glucose. For every 50 gram reduction in carbohydrate intake, there was an 8.9 mg/dl increase in 60-minute OGTT glucose (P < 0.01) in an adjusted model. Lower carbohydrate intake was also associated with higher 30-minute (adjusted ß = -6.5 mg/dl, P < 0.01) and 120-minute OGTT glucose (adjusted ß = -8.1 mg/dl, P = 0.01) and AUC (adjusted ß = -767, P < 0.01). CONCLUSIONS: Carbohydrate intake in the day preceding an OGTT in pregnancy is associated with post-load glucose values, with lower carbohydrate intake predicting higher glucose levels and higher carbohydrate intake predicting lower glucose levels. Carbohydrate restriction or excess before an OGTT may affect GDM diagnosis.