Relationship between normal oral glucose tolerance test in women at risk for gestational diabetes and large for gestational age infants.

Abstract

OBJECTIVE: To determine whether the glycemic status of pregnant women with a normal 3-h 100-g oral glucose tolerance test (OGTT) is related to outcome with respect to large for gestational age (LGA) infants. RESEARCH DESIGN AND METHODS: A prospective study of 2631 women was conducted. One hundred seventy-six women had an OGTT based either on a 1-h 50-g OGTT (n = 105) or clinical risk factors (n = 71). Thirty-three women were diagnosed as having gestational diabetes mellitus. RESULTS: Negligible discriminatory capacity for the variables with respect to prediction of LGA infants was indicated by the areas under the receiver operating characteristic (ROC) curves for fasting blood glucose, 2-h OGTT blood glucose, and the OGTT response curve area for women with a normal OGTT (n = 143). However, a statistically significant increased incidence of LGA infants was established for both the OGTT-positive and normal OGTT groups (P less than 0.0001). Multiparity, a maternal weight greater than or equal to 70 kg, and birth of a male infant were other factors associated with a significantly increased frequency of LGA infants. CONCLUSIONS: The results may be interpreted as either indicating a role for confounding variables, i.e., maternal weight, multiparity, and birth of a male infant, or the imprecision of the OGTT in assessing physiologically important changes in maternal hyperglycemia.