Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objective: To assess the accuracy of a Latin-American curve used to predict adverse pregnancy outcomes such as low birth weight (LBW), small for gestational age (SGA), large for gestational age (LGA). Methods: More than 23 000 body mass index (BMI) measurements from 4540 pregnant women participating in a prospective cohort study conducted in 6 Brazilian capitals were analyzed in their relationship to LBW, SGA, LGA, and macrosomia. Analyses were based Oil receiver operating characteristic curves and models for repeated measures. Results: The areas under the curve were less than 0.70 for all outcomes, with low sensitivity and specificity for pregestational BMI (0.54-0.61) and BMI at the last prenatal visit (0.63-0.68). The longitudinal model showed a mean weekly BMI gain of 0.16. Conclusion: The Latin-American curve is inadequate to predict LBW, SGA, and LGA suggesting the need to develop a new approach for the nutritional monitoring of pregnant women. (C) 2009 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.1063223226Brazilian Ministry of HealthPan-American Health OrganizationFoundation for the Support of Research of the State of Rio Grande do Sul (FAPERGS)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)