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

Abstract 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 21st curves. Results Reference curves for estimated fetal weight were developed for a local population. The coefficient of determination was R2 = 99.11%, indicating that 99.11% of the fetal weight variations were explained by the model. Compared with Hadlock curves, the 50th, 90th, and 97th percentiles in this model were lower, whereas the 10th percentile nearly overlapped, and the 3rd percentile was slightly higher in the proposed model. The percentiles were higher in the proposed model compared with the Intergrowth 21st curves, particularly for the 3rd, 10th, and 50th 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.

### 摘要
#### 研究目的
制定巴西南部库里蒂巴本地人群的估算胎儿体重（Estimated Fetal Weight）参考曲线，并将其与其他人群建立的参考曲线进行对比。
#### 研究方法
本研究为回顾性观察性横断面研究。纳入2211例存在生长异常低风险、胎龄明确的单胎妊娠本地样本，构建估算胎儿体重的参考模型，并将该模型与哈德洛克（Hadlock）曲线及Intergrowth 21st曲线进行图形化对比。
#### 研究结果
本研究成功建立本地人群的估算胎儿体重参考曲线。模型决定系数R²=99.11%，表明该模型可解释99.11%的胎儿体重变异。与哈德洛克曲线相比，本模型的第50、90、97百分位数更低，第10百分位数几乎重合，第3百分位数略高；与Intergrowth 21st曲线相比，本模型各百分位数均更高，尤以第3、10、50百分位数为显著。
#### 研究结论
本研究建立了巴西南部库里蒂巴本地人群的估算胎儿体重参考曲线。所提出的模型与其他现有模型存在差异，此类差异可能源于模型构建时所采用的研究人群不同。