Comparison of sonographic fetal weight estimation formulas in patients with preterm premature rupture of membranes

Abstract

Background Estimation of fetal weight (EFW) by ultrasound is useful in clinical decision-making. Numerous formulas for EFW have been published but have not been validated in pregnancies complicated by preterm premature rupture of membranes (PPROM). The purpose of this study is to compare the accuracy of EFW formulas in patients with PPROM, and to further evaluate the performance of the most commonly used formula - Hadlock IV. Methods A retrospective cohort study of women with singleton gestations and PPROM, admitted to a single tertiary center between 2005 and 2017 from 220/7–330/7 (n = 565). All women had an EFW within 14 days of delivery by standard biometry (biparietal diameter, head circumference, abdominal circumference and femur length). The accuracy of previously published 21 estimated EFW formulas was assessed by comparing the Pearson correlation with actual birth weight, and calculating the random error, systematic error, proportion of estimates within 10% of birth weight, and Euclidean distance. Results The mean gestational was 26.8 ± 2.4 weeks at admission, and 28.2 ± 2.6 weeks at delivery. Most formulas were strongly correlated with actual birth weight (r > 0.9 for 19/21 formulas). Mean systematic error was − 4.30% and mean random error was 14.5%. The highest performing formula, by the highest proportion of estimates and lowest Euclidean distance was Ott (1986), which uses abdominal and head circumferences, and femur length. However, there were minimal difference with all of the first 10 ranking formulas. The Pearson correlation coefficient for the Hadlock IV formula was strong at r = 0.935 (p < 0.001), with 319 (56.5%) of measurements falling within 10%, 408 (72.2%) within 15% and 455 (80.5%) within 20% of actual birth weight. This correlation was unaffected by gender (r = 0.936 for males, r = 0.932 for females, p < 0.001 for both) or by amniotic fluid level (r = 0.935 for mean vertical pocket < 2 cm, r = 0.943 for mean vertical pocket ≥2 cm, p < 0.001 for both). Conclusions In women with singleton gestation and PPROM, the Ott (1986) formula for EFW was the most accurate, yet all of the top ten ranking formulas performed quite well. The commonly used Hadlock IV performed quite similarly to Ott’s formula, and is acceptable to use in this specific setting.

Application of ultrasonographic human estimated foetal weight formulas to cynomolgus monkeys (Macaca fascicularis) at 129–132 days of gestation: A comparative study of estimated and actual birthweight

“…The Combs formula was initially reported to provide accurate estimates at the extremes as well as the normal range of human foetal weight (Combs et al., 1993 ). However, the accuracy of the Combs formula varies in small human fetuses, with subsequent studies reporting high accuracy (Esinler et al., 2015 ; Eze et al., 2015 ; Warshafsky et al., 2021 ), whereas others report lower accuracy (Abele et al., 2010 ; Dudley, 2005 ; Hammami et al., 2018 ; Hiwale, 2017 ; Warrander et al., 2020 ). It is noteworthy that some studies demonstrate high accuracy, despite the potential for decreased precision when EFW formula is applied to populations different from those for which the formula was initially developed (Akinola et al., 2009 ).…”

“…These methods have been widely employed in human studies to evaluate the performance of the EFW formulas (Abele et al., 2010; Geerts & Widmer, 2011; Hart et al., 2010; Hiwale et al., 2019; Hoopmann, Abele et al., 2010; Hoopmann, Bernau et al., 2010). Pearson's correlation coefficient was applied to examine the strength and direction of the relationship between EFW and ABW (Dimassi et al., 2015; Schild et al., 2004; Van Mieghem et al., 2009; Warshafsky et al., 2021), and the significance of the correlation was determined using p ‐values. Statistical significance was set at $$p$$ < 0.05.…”

“…The Combs formula was initially reported to provide accurate estimates at the extremes as well as the normal range of human foetal weight (Combs et al, 1993). However, the accuracy of the Combs formula varies in small human fetuses, with subsequent studies reporting high accuracy (Esinler et al, 2015;Eze et al, 2015;Warshafsky et al, 2021), whereas others report lower accuracy (Abele et al, 2010;Dudley, 2005;Hammami et al, 2018;Hiwale, 2017;Warrander et al, 2020).…”

The Impact of the Active Stage of Labor on Estimate Fetal Weight: A Prospective Cohort Study

“…Ashwal et al and Blitz et al performed the estimated fetal weight measurement within a week before birth in their study, while Karahanoğlu et al shortened this period to 72 hours. 1,5,6 In our study, we included pregnant women whose ultrasound examination was performed with in 24 hours before labor in order to determine fetal weight estimation with the highest accuracy.…”

“…Measuring fetal weight is useful for clinicians not only in the management of labor, but also in reducing perinatal morbidity and mortality associated with suspected complications with macrosomia, cephalopelvic incompatibility, and IUGR. 1,2 Macrosomic fetuses are at risk for shoulder dystocia, brachial plexus damage, clavicle fracture, and humerus fracture. For these reasons, it serves as an essential tool for assessing fetal health and complications during antenatal and labor.…”