Waist circumference in the prediction of obesity-related adverse pregnancy outcomes.

The aim of this study is to evaluate the diagnostic properties of waist circumference in the prediction of obesity-related gestational outcomes. Pregnant women 20 years or older were consecutively enrolled in six Brazilian State capitals from 1991 to 1995. Weight, height, and waist circumference were measured and an oral glucose tolerance test was performed. Patients were followed through childbirth by chart review. Diagnostic performance for the different outcomes, as measured by area under the receiver operating characteristic (ROC) curve, was estimated through logistic regression. Areas under the ROC curve (95%CI) for waist circumference were 0.621(0.589-0.652) for gestational diabetes, 0.640 (0.588-0.692) for preeclampsia, and 0.645(0.617-0.673) for macrosomia. These areas were similar to those for BMI (p > 0.05). A waist circumference of 82 cm jointly maximized sensitivity (63%) and specificity (57%). Cutoff points of 23 kg/m(2) for pre-pregnancy BMI and 26 kg/m(2) for BMI at enrollment produced similar diagnostic properties. In conclusion, waist circumference predicts obesity-related adverse pregnancy outcomes at least as well as BMI.