Accuracy of Fetal Weight Estimation by Ultrasonographic Evaluation in a Northeastern Region of India

Abstract

Background and Objectives. Fetal weight evaluation in utero is a significant component in obstetric practices. The present study aims to estimate the fetal weight (EFW) by evaluating two available formulas using ultrasound parameters and comparing them with actual birth weight (ABW) after delivery. The accuracy and efficacy of both EFW formulas in detecting intrauterine growth retardation (IUGR) and macrosomia were also compared in our local sample of the population. Methods. The cross-sectional study included 100 pregnant women aged 20–45 years from the Kamrup district admitted to Guwahati Medical College and Hospital, Guwahati, Assam. The data were analyzed using Microsoft Excel and SPSS version 16. The EFW at term was calculated using Shepard’s formula and Hadlock’s formula. Differences in means are compared using the one-way ANOVA or Kruskal–Wallis test and paired t-test. The accuracy of the two procedures was evaluated using mean absolute error (MAE) and mean absolute percentage error (MAPE). A p value<0.05 was considered significant. Results. The present study included 100 pregnant women aged 21–38 years with term or postterm pregnancies subjected to ultrasonographic evaluation within 72 hours of delivery. The mean (±s.d.) EFW by Shepard’s formula was 2716.05 (±332.38) g and Hadlock’s formula was 2740.44 (±353.23) g, respectively. For Hadlock’s formula, MAE ± s.d. was found to be higher (overall 84.59 ± 76.54) specifically in the weight category less than 2500 (106.42 ± 88.11) as compared to Shepard’s (overall MAE ± s.d = 79.86 ± 64.78, and among ABW < 2500 g, MAE ± s.d = 65.04 ± 61.02). The overall MAPE of Hadlock’s formula was 3.14% and that for Shepard’s formula was 2.91%, and the difference was not statistically significant. Both Shepard’s formula and Hadlock’s formula had a sensitivity of 92.85% in detecting IUGR, but Hadlock’s method had higher specificity (66%), higher PPV (86.67%), and higher NPV (80%). Conclusion. The ultrasonographic evaluation of fetal weight helps predict fetal birth weight precisely and can influence obstetric management decisions concerning timing and route of delivery, thus reducing perinatal morbidity and mortality.

Fetal weight estimation based on deep neural network: a retrospective observational study

“…In recent years several EFW prediction models have been developed, but none of these models were practiced in routine clinical applications or recommended according to the current guidelines. Hadlock’s formula is still thus far one of the best-established weight estimation formulas and the one most widely used in everyday routine work, despite recent studies indicating potential ways to decrease MAPE, the especially in macrosomic fetuses and other deviant cases [ 8 , 23 ]. Although, due to the drastic difference in the number of participants, the MAPE in this study was slightly higher than that calculated by Konwar [ 8 ] or Weiss [ 23 ] (5.79% for DNN estimation and 6.46% for Hadlock’s formula), the DNN model still predicted the EFW more accurately compared to the Hadlock’s formula.…”

“…Hadlock’s formula is still thus far one of the best-established weight estimation formulas and the one most widely used in everyday routine work, despite recent studies indicating potential ways to decrease MAPE, the especially in macrosomic fetuses and other deviant cases [ 8 , 23 ]. Although, due to the drastic difference in the number of participants, the MAPE in this study was slightly higher than that calculated by Konwar [ 8 ] or Weiss [ 23 ] (5.79% for DNN estimation and 6.46% for Hadlock’s formula), the DNN model still predicted the EFW more accurately compared to the Hadlock’s formula. Moreover, the frequency of samples with large deviation (> 500 g) was also significantly smaller compared to Hadlock’s formula, indicating that the DNN model can reduce large estimated errors.…”

“…With widespread ultrasound (US) examination during various stages of pregnancy, formulae based on US measurements became the most widely used method of EFW [ 5 ]. The formulae derived from regression models using various combinations of US parameters, such as Hadlock’s formula [ 6 ] and Warsof’s formula [ 7 ], were well established but still have 6.5–8% mean absolute percentage error (MAPE) [ 8 ]. Although formulae based on fetal thigh or upper arm volume measurements through 3-D US [ 9 ] and magnetic resonance echo-planar imaging [ 10 ] can predict EFW with higher accuracy, these approaches are time-consuming, expensive and technically challenging.…”

Comparison of Actual Birth Weight with the Ultrasonographic and Clinical Estimation of Fetal Birth Weight: A Prospective Study

“…Several studies have been done for comparing the USG fetal weight with actual birth weight. 11,12,13 A study conducted by Paravathavarthini et al showed that USG was closer to estimating the fetal weight than the actual birth weight. 14 Other studies have also shown that ultrasonographic estimation is more accurate in estimating fetal weight.…”

Comparison between Different Ultrasound Formulae for Accurate Estimation of Fetal Weight

“…Numerous sonographic formulas for determining fetal weight have been developed; however, the accuracy of these formulas varies among research. These disparities may be attributable to variables like differences in research populations, variations in biometric measures used, and inconsistencies in formula creation processes [5,6]. Therefore, a complete analysis of multiple formulas is required to discover the formula that consistently yields the best accurate fetal weight estimations.…”