BACKGROUND Ultrasonography has become an indispensible tool in the management of obstetric patients. Accurate determination of fetal gestational age (FGA) has posed great challenge to patient management as the accuracy of traditional biometric parameters decreases with advance in gestation age. Accuracy of fetal kidney length (FKL) in the determination of FGA at third trimester has been documented in other population. This study is aimed to create baseline reference values of fetal kidney lengths in a Nigerian population as previous studies show population specific variations. METHODS This prospective cross sectional study was carried out on 534 pregnant women between 20 and 40 weeks of gestation who met the inclusion criteria at Diamond Biomedical Services Ltd. A pilot study was conducted on 20 patients to determine the reproducibility and reliability of ultrasound measurement of FKL. Fetal kidney lengths were calculated as mean of three separate measurements. The 5th, 50th and 95th percentiles were calculated using least squared regression analysis. Third polynomial regression models were used to establish the relationship between right and left FKL and FGA. RESULTS Both FKL measurements are highly reproducible with excellent correlation and agreement within and between sonographers. It correlates strongly with gestational age while the relationships between right and left kidney lengths with gestational age were established using the following regression equations: RKL =  - 11.18 + 1.193 × FGA - 0.0350 × FGA2 + 0.00037 × FGA3 and LKL =  - 12.57 + 1.332 × FGA - 0.0390 × FGA2 + 0.00040 × FGA3 for right and left kidneys respectively. CONCLUSION Nigerian population specific baseline reference values of FKLs for the estimation of FGA should be adopted rather than relying on the Caucasians values as universal patterns.

中文翻译：

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通过尼日利亚Portharcourt孕妇的胎儿肾脏长度测量，对20至40周的胎龄进行超声检查。

背景技术超声检查已成为产科患者管理中必不可少的工具。胎儿胎龄（FGA）的准确确定给患者管理带来了巨大挑战，因为传统生物特征参数的准确性随着胎龄的增加而降低。在其他人群中，已记录了在妊娠中期测定FGA的胎儿肾脏长度（FKL）的准确性。这项研究旨在创建尼日利亚人群中胎儿肾脏长度的基线参考值，因为先前的研究显示了特定人群的变异。方法这项前瞻性横断面研究是针对534个妊娠期在20至40周之间且符合Diamond Biomedical Services Ltd纳入标准的孕妇进行的。对20名患者进行了一项初步研究，以确定FKL超声测量的可重复性和可靠性。将胎儿肾脏的长度计算为三个单独测量值的平均值。使用最小二乘回归分析计算第5，第50和第95个百分位数。第三多项式回归模型用于建立左右FKL和FGA之间的关系。结果两种FKL测量值均具有很高的可重复性，并且在超声检查者之间以及超声检查者之间具有良好的相关性和一致性。它与胎龄密切相关，而左右肾脏长度与胎龄之间的关系通过以下回归方程建立：RKL =-11.18 + 1.193×FGA-0.0350×FGA2 + 0.00037×FGA3和LKL =-12.57 + 1.332× FGA-0.0390×FGA2 + 0。右肾和左肾分别为00040×FGA3。结论应采用尼日利亚人群特定的FKL基线参考值来估算FGA，而不是将白种人值作为通用模式。