Comparison of eleven commonly used formulae for sonographic estimation of fetal weight in prediction of actual birth weight

Abstract

Objectives: The aim of the study is to compare the accuracy of 11 formulas in predicting fetal weight. Material and methods: The study includes 1072 pregnant women of gestational age from 28 to 42 weeks, who gave birth between January and June 2017. Pregnant women were divided into five groups; group 1, where actual birth weight (ABW) was less than 2500 g, group 2, where ABW was between 2500-4000 g, group 3, where ABW was above 4000 g. Group 4-newborns with birth weight under 10 percentile and group 5-newborns with birth weight above 90 percentile. The accuracy of the estimated fetal weight (EFW) was assessed by calculating absolute percentage error (APE) and 'limits-of-agreement'. R Spearman correlation was utilized between EFW and ABW. Results: The most accurate formula for group 1 is Hadlock3 (MAPE = 7.04%), the narrowest limits of agreement has Combs-[mean (SD): 99.41 g (269.57 g)]. For group 2, the lowest MAPE (5.43%) has Ott, the narrowest limits of agreement belongs to Combs-[mean (SD):-101.36 g (275.88 g)]. For group 3 is Hadlock3 (MAPE = 5.79%), the narrowest limits of agreement has Hadlock5 [mean (SD):-637.32 g (209.59 g)]. For group 4 is Combs (MAPE = 7.72%), the narrowest limits of agreement has Combs [mean (SD): 195.77 g (264.97 g)]. For gr oup 5 is Warsof2 (MAPE = 7.06%), the narrowest limits of agreement has Campbell [mean (SD): 227.81 g (299.26 g)]. Conclusions: Median of absolute percentage error is the most useful parameter to predict birth weight. Each group of fetuses needs different formula to predict the most accurate weight.

Integrated growth assessment in the first 1000 d of life: an interdisciplinary conceptual framework

“…However, 10–15 % errors in estimated foetal weight v . actual weight are not uncommon and may be attributed to high inter- and intra-observer variability in biometric measurements, the choice of equation and the amplification of errors in single parameters when included in a calculation ( 28 , 38 – 42 ) .…”

“…(2) References/standards: -Serial measurements can be plotted on same growth charts as individual biometric measurements -Various methods to quantify growth velocity (44) (including individualised growth charts (2)), but none are widely implemented in practice Cut-offs: Delphi Consensus Statement for FGR* includes downward crossing of more than two quartiles (43) Foetal body composition Ultrasonography: -Subcutaneous fat thickness -Organ size Gestational age-related Foetal body composition is not routinely assessed, and no universally acknowledged references/standards or cutoffs exist; organ size measurements may be used to assess foetal health conditions (38) *Delphi Consensus Statement for Foetal Growth Restriction (43) International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) (34) . However, 10-15 % errors in estimated foetal weight v. actual weight are not uncommon and may be attributed to high inter-and intra-observer variability in biometric measurements, the choice of equation and the amplification of errors in single parameters when included in a calculation (28,(38)(39)(40)(41)(42) . The aim of foetal growth assessment is the detection of FGR or excessive foetal growth.…”

Predicting fetal weight by three-dimensional limb volume ultrasound (AVol/TVol) and abdominal circumference

“…Many factors affect the accuracy of the assessment, including the abnormal fetus, large deviation in data collection of AC and HC, and difficulty in obtaining accurate measurement section due to examination conditions in late pregnancy. Plonka et al [31] showed that fetuses with different conditions should be assessed with different formulas. Dimassi et al [32] showed that ultrasound examination in the delivery room was reasonable, but the accuracy rate of EFW was only 62.1%.…”

Estimation of Fetal Weight by Clinical Methods and Ultrasonography and Comparing With Actual Birth Weight

“…stimation of Fetal Weight (EFW) is an essential key in the decision-making process for obstetric planning and management [1,2]. Assessment of fetal weight is an essential part of predicting fetal weight disorders that include intrauterine growth disorders (weight less than 10% relative to gestational age) and macrosomia (weight more than 90% relative to gestational age) [3,4]. To prevent the fetal, neonatal, and maternal morbidities and mortalities associated with Intrauterine Growth Retardation (IUGR) and macrosomia neonates, accurate estimation of fetal weight is very important [5].…”