The impact of maternal age, body mass index and maternal weight gain on the glucose challenge test in pregnancy.

Objective: The aim of this study was to determine whether maternal age, prepregnancy and mid-trimester body mass index (BMI), or excessive mid-pregnancy weight gain predict abnormal glucose challenge test (GCT) results.

Methods: A retrospective chart review of 75 consecutive singleton pregnancies was performed. Patients were screened at 24-28 weeks of gestation with a 50-g oral GCT. Prepregnancy BMI and pregnancy weight gain up to the time of GCT testing, as well as other demographic data, were recorded. Statistical analysis included regression analysis and Student's t-test, receiver-operator characteristic curve and multivariate logistic regression.

Results: Maternal age and prepregnancy and mid-trimester BMI were significantly higher in women with an abnormal GCT (p<0.05). A direct correlation was found between these parameters and GCT results (R(2)=0.08, R(2)=0.102 and R(2)=0.116, respectively; p<0.05). Mid-trimester maternal BMI of >or=30 kg/m(2) and maternal age >or=32 years are the optimal predictors of abnormal GCT results.

Conclusions: Mid-trimester maternal BMI of >or=30 kg/m(2) and maternal age >or=32 years are useful predictors of abnormal GCT results. We suggest that these factors should also be considered when selective screening for gestational diabetes mellitus is practiced.