Influence of lower cutoff values for 100-g oral glucose tolerance test and glycemic profile for identification of pregnant women at excessive fetal growth risk.
OBJECTIVE
To evaluate data from patients with normal oral glucose tolerance test (OGTT) results and a normal or impaired glycemic profile (GP) to determine whether lower cutoff values for the OGTT and GP (alone or combined) could identify pregnant women at risk for excessive fetal growth.


METHODS
We classified 701 pregnant women with positive screening for gestational diabetes mellitus (GDM) into 2 categories -- (1) normal 100-g OGTT and normal GP and (2) normal 100-g OGTT and impaired GP-to evaluate the influence of lower cutoff points in a 100-g OGTT and GP (alone or in combination) for identification of pregnant women at excessive fetal growth risk. The OGTT is considered impaired if 2 or more values are above the normal range, and the GP is impaired if the fasting glucose level or at least 1 postprandial glucose value is above the normal range. To establish the criteria for the OGTT (for fasting and 1, 2, and 3 hours after an oral glucose load, respectively), we considered the mean (75 mg/dL, 120 mg/dL, 113 mg/dL, and 97 mg/dL), mean plus 1 SD (85 mg/dL, 151 mg/dL, 133 mg/dL, and 118 mg/dL), and mean plus 2 SD (95 mg/dL, 182 mg/dL, 153 mg/dL, and 139 mg/dL); and for the GP, we considered the mean and mean plus 1 SD (78 mg/dL and 92 mg/dL for fasting glucose levels and 90 mg/dL and 130 mg/dL for 1- or 2-hour postprandial glucose levels, respectively).


RESULTS
Subsequently, the women were reclassified according to the new cutoff points for both tests (OGTT and GP). Consideration of values, in isolation or combination, yielded 6 new diagnostic criteria. Excessive fetal growth was the response variable for analysis of the new cutoff points. Odds ratios and their respective confidence intervals were estimated, as were the sensitivity and specificity related to diagnosis of excessive fetal growth for each criterion. The new cutoff points for the tests, when used independently rather than collectively, did not help to predict excessive fetal growth in the presence of mild hyperglycemia.


CONCLUSIONS
Decreasing the cutoff point for the 100-g OGTT (for fasting and 1, 2, and 3 hours) to the mean (75 mg/dL, 120 mg/dL, 113 mg/dL, and 97 mg/dL) in association with the GP (mean or mean plus 1 SD-78 mg/dL and 92 mg/dL for the fasting state and 90 mg/dL and 130 mg/dL for 1- or 2-hour postprandial values-increased the sensitivity and specificity, and both criteria had statistically significant predictive power for detection of excessive fetal growth.
Rudge
Marilza V C
MV
Department of Gynecology, Obstetrics and Mastology, Botucatu Medical School, São Paulo State University, São Paulo, Brazil.
Lima
Carlos A B
CA
Paulette
Teresa A L
TA
Jovanovic
Lois
L
Negrato
Carlos A
CA
Rudge
Cibele V C
CV
Calderon
Iracema M P
IM
Dias
Adriano
A
Atallah
Alvaro N
AN
D000328:Adult; D001786:Blood Glucose; D016640:Diabetes, Gestational / Q000097:blood / Q000175:diagnosis*; D005260:Female; D005865:Gestational Age; D005951:Glucose Tolerance Test; D038321:Glycemic Index; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D012307:Risk Factors
D001786:Blood Glucose