Local References for Ultrasound-Estimated Fetal Weight Based on 2,211 Singleton Pregnancies in the City of Curitiba, South of Brazil

Objective To develop reference curves of estimated fetal weight for a local population in Curitiba, South of Brazil, and compare them with the curves established for other populations. Methods An observational, cross-sectional, retrospective study was conducted. A reference model for estimated fetal weight was developed using a local sample of 2,211 singleton pregnancies with low risk of growth disorders and well-defined gestational age. This model was compared graphically with the Hadlock and Intergrowth 21 curves. Results Reference curves for estimated fetal weight were developed for a local population. The coefficient of determination was R = 99.11%, indicating that 99.11% of the fetal weight variations were explained by the model. Compared with Hadlock curves, the 50 , 90 , and 97 percentiles in this model were lower, whereas the 10 percentile nearly overlapped, and the 3 percentile was slightly higher in the proposed model. The percentiles were higher in the proposed model compared with the Intergrowth 21 curves, particularly for the 3 , 10 , and 50 percentiles. Conclusion We provide a local reference curve for estimated fetal weight. The proposed model was different from other models, and these differences might be due to the use of different populations for model construction.