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Monier I, Ego A, Benachi A, Ancel PY, Goffinet F, Zeitlin J. Comparison of the Hadlock and INTERGROWTH formulas for calculating estimated fetal weight in a preterm population in France. Am J Obstet Gynecol 2018; 219:476.e1-476.e12. [PMID: 30118693 DOI: 10.1016/j.ajog.2018.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/31/2018] [Accepted: 08/07/2018] [Indexed: 01/30/2023]
Abstract
BACKGROUND Accurate estimation of fetal weight is needed for growth monitoring and decision-making in obstetrics; the INTERGROWTH project developed an estimated fetal weight formula to construct new intrauterine growth standards. OBJECTIVE We sought to compare the accuracy of the Hadlock and INTERGROWTH formulas for the estimation of fetal weight among preterm infants. STUDY DESIGN Using the EPIPAGE 2 population-based study of births between 22-34 weeks of gestation, we included 578 nonanomalous singleton fetuses with an ultrasound-to-delivery interval <2 days. We used abdominal circumference, head circumference, and femur length to calculate estimated fetal weight with Hadlock formula and abdominal and head circumferences to calculate estimated fetal weight according to INTERGROWTH. The mean percentage errors and the proportions of estimated fetal weight measures within ±10% of birthweight were compared between the 2 methods. RESULTS Mean (SD) gestational age and birthweight were 29.1 (SD 2.7) weeks and 1219 (SD 489) g. Mean (SD) percentage errors for Hadlock and INTERGROWTH were significantly different: -0.7 (SD 10.1) and -3.5 (SD 11.6), respectively (P < .001), and more infants were classified within ±10% of their birthweight with Hadlock compared to INTERGROWTH (68.7% vs 57.8%, P < .001). The INTERGROWTH formula overestimated birthweight at 22-23 weeks compared to Hadlock [mean errors of 18.8 (SD 13.6) vs 5.5 (SD 10.2)] and underestimated birthweight >28 weeks: at 29-31 weeks, mean errors were -5.8 (SD 10.9) for INTERGROWTH and -0.6 (SD 10.4) for Hadlock. CONCLUSION Hadlock estimated fetal weight formula was more accurate than INTERGROWTH formula for fetuses delivered between 22-34 weeks of gestation. Our results support continued use of Hadlock formula in France and raise questions about the applicability of INTERGROWTH intrauterine growth standards.
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de Lima AMH, de Carvalho PRN, Junior SCG, Carioca ACC, Lopes JMDA. Analysis of the Performance of 11 Formulae for Fetal Weight Estimation in Preterm Fetuses with Abnormal Doppler Velocimetry - A Retrospective Multicenter Study. REVISTA BRASILEIRA DE GINECOLOGIA E OBSTETRÍCIA 2018; 40:580-586. [PMID: 30235474 PMCID: PMC10467365 DOI: 10.1055/s-0038-1670643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVE To assess 11 formulae commonly used to estimate fetal weight in a population of premature fetuses who had abnormal Doppler velocimetry due to early-onset placental insufficiency. The performance of each formula was evaluated in subgroups of fetuses with expected growth and intrauterine growth restriction. METHODS Data were collected from fetuses and mothers who delivered at three Brazilian hospitals between November 2002 and December 2013. We used the following formulae: Campbell; Hadlock I, II, III, IV and V; Shepard; Warsof; Weiner I and II; and Woo III. RESULTS We analyzed 194 fetuses. Of these, 116 (59.8%) were considered appropriate for gestational age (AGA), and 103 (53.1%) were male. The amniotic fluid volume was reduced in 87 (44.8%) fetuses, and the umbilical artery Doppler revealed absence or inversion of diastolic flow in 122 (62.9%) cases, and the analysis of the ductus venosus revealed abnormal flow in 60 (34.8%) fetuses. The Hadlock formulae using three or four fetal biometric parameters had low absolute percentage error in the estimated fetal weight among preterm fetuses with abnormal Doppler studies who were born within 5 days of the ultrasound evaluation. The results were not influenced by the clinical and ultrasound parameters often found in early-onset placental insufficiency. CONCLUSION In this study, the formulae with the best performance for fetal weight estimation in the analyzed population were Hadlock I and IV, which use four and three fetal biometric parameters respectively to estimate the weight of preterm fetuses with abnormal Doppler studies.
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Affiliation(s)
| | - Paulo Roberto Nassar de Carvalho
- Diagnostic Center, Clínica Perinatal Laranjeiras, Rio de Janeiro, RJ, Brazil
- Fetal Medicine Center, Instituto Nacional Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Saint Clair Gomes Junior
- Fetal Medicine Center, Instituto Nacional Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Ana Carolina Costa Carioca
- Fetal Medicine Center, Instituto Nacional Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - José Maria de Andrade Lopes
- Diagnostic Center, Clínica Perinatal Laranjeiras, Rio de Janeiro, RJ, Brazil
- Fetal Medicine Center, Instituto Nacional Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
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Peyronnet V, Kayem G, Mandelbrot L, Sibiude J. Détection des fœtus petits pour l’âge gestationnel lors de l’échographie du troisième trimestre. Étude observationnelle monocentrique. ACTA ACUST UNITED AC 2016; 44:531-6. [DOI: 10.1016/j.gyobfe.2016.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/07/2016] [Indexed: 10/21/2022]
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Gabbay-Benziv R, Aviram A, Bardin R, Ashwal E, Melamed N, Hiersch L, Wiznitzer A, Yogev Y, Hadar E. Prediction of Small for Gestational Age: Accuracy of Different Sonographic Fetal Weight Estimation Formulas. Fetal Diagn Ther 2016; 40:205-213. [DOI: 10.1159/000443881] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/28/2015] [Indexed: 11/19/2022]
Abstract
Objective: To compare the accuracy of various sonographic estimated fetal weight (sEFW) formulas for the prediction of small for gestational age (SGA) neonates. Methods: A retrospective analysis of 6,126 fetal biometrical measurements performed within 3 days of delivery. SGA prediction was evaluated for various sEFW formulas by calculating the sensitivity, specificity, positive/negative predictive value (PPV/NPV), likelihood ratio (+LR/-LR), overall accuracy and area under the receiver operating characteristic curve (AUC). Systematic error, random error, proportion of estimates >10% of birth weights, actual and absolute weight differences were compared between SGA and non-SGA neonates. Results: Overall, 638 (10.4%) neonates were SGA. There was considerable variation among formulas in sensitivity (mean ± SD, 62 ± 14.4%; range, 32.4-91.2), PPV (72.5 ± 10.7%; 45.8-95.6) and +LR (24.2 ± 10.9; 7.2-57.3), mild variation in specificity (96.6 ± 2.7%; 87.4-99.4), NPV (94.6 ± 5.3%; 72.2-98.9) and -LR (0.4 ± 0.1; 0.1-0.7) and minimal variation in AUC (mean, 0.93; range, 0.91-0.93). The majority of formulas had a lower accuracy for the SGA neonates, with systematic error and random error ranging from -4.2 to 14.3% and from 8.4 to 12.9% for SGA, and from -8.7 to 16.1% and from 7.2 to 10.5% for non-SGA, respectively. Conclusion: sEFW formulas differ in their accuracy for SGA prediction. In our population, the most accurate formula for SGA prediction was Hadlock's formula utilizing femur length, abdominal and head circumference.
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Melamed N, Ryan G, Windrim R, Toi A, Kingdom J. Choice of Formula and Accuracy of Fetal Weight Estimation in Small-for-Gestational-Age Fetuses. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2016; 35:71-82. [PMID: 26635253 DOI: 10.7863/ultra.15.02058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/27/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVES The purpose of this study was to identify the most accurate sonographic models for fetal weight estimation in specific subgroups of small-for-gestational-age (SGA) fetuses. METHODS We conducted a retrospective study of women who delivered an SGA neonate and underwent a sonographic estimation of fetal weight within 7 days of delivery in a single tertiary center (n = 370). The accuracy of fetal weight estimation was compared for 33 sonographic models (27 nontargeted and 6 targeted SGA- or low-birth-weight-specific models) in specific subgroups of SGA fetuses: early versus late SGA, asymmetric versus symmetric, and presence of Doppler abnormalities. RESULTS A wide variation in the accuracy of the different models was found (systematic error, -12.5% to 15.1%; random error, 7.8% to 15.5%). Most nontargeted models tended to systematically overestimate the weight of SGA fetuses. The best performing model in the overall SGA group was the targeted model of Scott et al (J Ultrasound Med 1996; 15:669-672; systematic error ± random error, -2.8% ± 8.3%). However, the optimal models varied for different subgroups of SGA fetuses, and in most cases the targeted models were the most accurate. An approach that used the optimal model for each subgroup of SGA fetuses compared with the uniform use of the model of Scott et al for all SGA fetuses was associated with a lower systematic error (-0.38% versus -2.8%; P < .001) and a higher proportion of weight estimations within 5%, 10%, and 15% of birth weight (48.4% versus 40.8%; P= .038; 78.6% versus 71.4%; P= .022; 95.1% versus 89.2%; P = .003, respectively). CONCLUSIONS Sonographic models in current use for fetal weight estimation in SGA fetuses have significant errors, and their performance varies for specific subgroups of SGA fetuses. An approach that uses subgroup-specific models may improve the accuracy of weight estimation among SGA fetuses.
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Affiliation(s)
- Nir Melamed
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada (N.M.); Fetal Medicine Division (Placenta Clinic), Department of Obstetrics and Gynecology (G.R., R.W., J.K.), and Department of Medical Imaging (A.T.), Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
| | - Greg Ryan
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada (N.M.); Fetal Medicine Division (Placenta Clinic), Department of Obstetrics and Gynecology (G.R., R.W., J.K.), and Department of Medical Imaging (A.T.), Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Rory Windrim
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada (N.M.); Fetal Medicine Division (Placenta Clinic), Department of Obstetrics and Gynecology (G.R., R.W., J.K.), and Department of Medical Imaging (A.T.), Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Ants Toi
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada (N.M.); Fetal Medicine Division (Placenta Clinic), Department of Obstetrics and Gynecology (G.R., R.W., J.K.), and Department of Medical Imaging (A.T.), Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - John Kingdom
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada (N.M.); Fetal Medicine Division (Placenta Clinic), Department of Obstetrics and Gynecology (G.R., R.W., J.K.), and Department of Medical Imaging (A.T.), Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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Huber C, Zdanowicz JA, Mueller M, Surbek D. Factors influencing the accuracy of fetal weight estimation with a focus on preterm birth at the limit of viability: a systematic literature review. Fetal Diagn Ther 2014; 36:1-8. [PMID: 24863502 DOI: 10.1159/000358518] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND Fetal weight estimation (FWE) is an important factor for clinical management decisions, especially in imminent preterm birth at the limit of viability between 23(0/7) and 26(0/7) weeks of gestation. It is crucial to detect and eliminate factors that have a negative impact on the accuracy of FWE. DATA SOURCES In this systematic literature review, we investigated 14 factors that may influence the accuracy of FWE, in particular in preterm neonates born at the limit of viability. RESULTS We found that gestational age, maternal body mass index, amniotic fluid index and ruptured membranes, presentation of the fetus, location of the placenta and the presence of multiple fetuses do not seem to have an impact on FWE accuracy. The influence of the examiner's grade of experience and that of fetal gender were discussed controversially. Fetal weight, time interval between estimation and delivery and the use of different formulas seem to have an evident effect on FWE accuracy. No results were obtained on the impact of active labor. DISCUSSION This review reveals that only few studies investigated factors possibly influencing the accuracy of FWE in preterm neonates at the limit of viability. Further research in this specific age group on potential confounding factors is needed.
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Affiliation(s)
- Chantal Huber
- Department of Obstetrics and Gynaecology, Bern University Hospital, Bern, Switzerland
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Stefanelli S, Groom KM. The accuracy of ultrasound-estimated fetal weight in extremely preterm infants: a comparison of small for gestational age and appropriate for gestational age. Aust N Z J Obstet Gynaecol 2014; 54:126-31. [PMID: 24571274 DOI: 10.1111/ajo.12198] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 01/24/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To compare the accuracy of estimated fetal weight (EFW) in extremely preterm small for gestational age (SGA) and appropriate for gestational age (AGA) infants and report other significant factors influencing the accuracy of EFW. METHODS A retrospective cohort study of singleton pregnancies 22(+0) -27(+6) weeks. Women were included in the study if an ultrasound scan had been performed within seven days of delivery, with no major fetal anomaly and data available to calculate customised birthweight (BW) centiles. Mean error of EFW and actual BW and mean % error of EFW and actual birthweight were compared for SGA and AGA infants. A stepwise backward elimination linear regression model was used to determine the significant factors influencing the accuracy of EFW. RESULTS A total of 134 cases (51 SGA and 83 AGA) were analysed. The mean gestational age at delivery was 25(+2) weeks (SD 11.5 days) and mean BW 711 g (SD 227 g). Overall mean percentage error of EFW and actual BW was 8.8% (range 0-34.6%). There was a significant difference in mean error of EFW and actual BW for SGA and AGA deliveries (mean +16 g versus -23 g, respectively, P = 0.01) and in mean % error of EFW (11.2%, 95%CI 9.1-13.3 versus 7.4%, 95% CI 6.2-8.6 P = 0.009). Factors that significantly influenced the accuracy of EFW included SGA (P = 0.001, coeff. = -3.73, 95% CI -5.94/-1.52), scan to delivery interval (P = 0.02, coeff. = 0.66, 95% CI 0.12/1.21) and reduced amniotic fluid (P = 0.008, coeff = 3.61, 95% CI -5.47/-0.85). CONCLUSIONS Ultrasonographic EFW for extreme preterm SGA fetuses is less accurate than AGA fetuses and is more likely to overestimate EFW. This should be considered when counselling women with growth restricted fetuses at the limits of viability.
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Affiliation(s)
- Sergio Stefanelli
- Department of Obstetrics and Gynaecology, National Women's Health, Auckland City Hospital, Auckland, New Zealand
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Grangé G. Modalités de dépistage et de diagnostic du fœtus petit pour l’âge gestationnel. ACTA ACUST UNITED AC 2013; 42:921-8. [DOI: 10.1016/j.jgyn.2013.09.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Geerts L, Widmer T. Which is the most accurate formula to estimate fetal weight in women with severe preterm preeclampsia? J Matern Fetal Neonatal Med 2011; 24:271-9. [PMID: 21231823 DOI: 10.3109/14767058.2010.485232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To identify the most accurate formula to estimate fetal weight (EFW) from ultrasound parameters in severe preterm preeclampsia. METHODS In a prospective study, serial ultrasound assessments were performed in 123 women with severe preterm preeclampsia. The EFW, calculated for 111 live born, normal, singleton fetuses within 7 days of delivery using 38 published formulae, was compared to the actual birth weight (ABW). Accuracy was assessed by correlations, mean (absolute and signed) (%) errors, % correct predictions within 5-20% of ABW and limits of agreement. RESULTS Accuracy was highly variable. Most formulae systematically overestimated ABW. Five Hadlock formulae utilizing three or four variables and Woo 3 formula had the highest accuracy and did not differ significantly (mean absolute % errors 6.8-7.2%, SDs 5.3-5.8%, > 75% of estimations within 10% of ABW and 95% limits of agreement between -18/20% and +14/15%). They were not negatively affected by clinical variables but had some inconsistency in bias over the ABW range. All other formulae, including those targeted for small, preterm or growth restricted fetuses, were inferior and/or affected by multiple clinical variables. CONCLUSION In this GA window, Hadlock formulae using three or four variables or Woo 3 formula can be recommended.
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Affiliation(s)
- Lut Geerts
- Department of Obstetrics and Gynaecology, Tygerberg Hospital, University of Stellenbosch, South Africa.
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Mohammadi H, Nemati M, Allahmoradi Z, Raissi HF, Esmaili SS, Sheikhani A. Ultrasound estimation of fetal weight in twins by artificial neural network. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/jbise.2011.41006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abele H, Hoopmann M, Wagner N, Hahn M, Wallwiener D, Kagan KO. Accuracy of sonographic fetal weight estimation of fetuses with a birth weight of 1500g or less. Eur J Obstet Gynecol Reprod Biol 2010; 153:131-7. [DOI: 10.1016/j.ejogrb.2010.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 06/06/2010] [Accepted: 07/04/2010] [Indexed: 10/19/2022]
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Skupski DW, McCullough LB, Levene M, Chervenak FA. Improving obstetric estimation of outcomes of extremely premature neonates: an evolving challenge. J Perinat Med 2010; 38:19-22. [PMID: 19958213 DOI: 10.1515/jpm.2010.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIMS A clinically useful website at the US National Institutes of Child Health and Human Development (NICHD) uses an algorithm based on a recent publication to estimate peri-viable neonatal outcomes. This algorithm uses gestational age, ultrasound estimated fetal weight (EFW), fetal sex, and the use of antenatal corticosteroids as the basis for estimation of outcomes and when used after birth is superior to such estimation by gestational age alone. Because one might be tempted to use this algorithm with obstetric patients, we tested its clinical applicability. METHODS We reviewed the literature using search terms relating to the above clinical factors. Next, we gathered data from the website. The range of outcomes for neonates was then estimated using the uncertainty derived for these clinical factors before birth from the literature review and the NICHD website algorithm. RESULTS We found increased uncertainty for estimating outcomes, as a function of the greater uncertainty in knowledge of the clinical factors in obstetrics as opposed to neonatology. CONCLUSIONS The imprecision during the time before birth seriously restricts the obstetric use of the NICHD algorithm at this time. Refining the precision of the algorithm prior to birth is necessary.
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Affiliation(s)
- Daniel W Skupski
- Obstetrics and Gynecology, Weill Medical College of Cornell University, The New York Hospital Queens, Flushing, NY 11355, USA.
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Melamed N, Yogev Y, Meizner I, Mashiach R, Bardin R, Ben-Haroush A. Sonographic fetal weight estimation: which model should be used? JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2009; 28:617-629. [PMID: 19389901 DOI: 10.7863/jum.2009.28.5.617] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE The purpose of this study was to compare the accuracy of different sonographic models for fetal weight estimation. METHODS We evaluated 26 different models using 3705 sonographic weight estimations performed less than 3 days before delivery. Models were ranked on the basis of systematic and random errors and were grouped according to the combination of biometric indices in each model. Cluster analysis was used to compare the accuracy of the different model groups. RESULTS A considerable variation in the accuracy of the different models was found. For birth weights (BWs) in the range of 1000 to 4500 g, models based on 3 or 4 fetal biometric indices were significantly more accurate than models that incorporated only 1 or 2 indices. The accuracy of weight estimation decreased at the extremes of BWs, leading to overestimation in low-BW categories as opposed to underestimation when the BW exceeded 4000 g. The precision of most models was lowest in the low-BW groups. CONCLUSIONS To improve the accuracy of fetal weight estimation, sonographic models that are based on 3 or 4 fetal biometric indices should be preferred. Recognizing the accuracy and the tendency for underestimation or overestimation of each of the available models is important for the judicious interpretation of fetal weight estimations, especially at the extremes of fetal weight.
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Affiliation(s)
- Nir Melamed
- Department of Obstetrics and Gynecology, Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.
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Ben-Haroush A, Melamed N, Mashiach R, Meizner I, Yogev Y. New regression formulas for sonographic weight estimation within 10, 7, and 3 days of delivery. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2008; 27:1553-1558. [PMID: 18946093 DOI: 10.7863/jum.2008.27.11.1553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVES The purpose of this study was to develop new regression formulas based on large numbers of sonographic examinations performed within 10, 7, and 3 days of delivery. METHODS Sonographic fetal biometric measurements and delivery ward data for an unselected population were analyzed. Multivariate linear regression models were fitted to the sonographic data to predict the actual birth weight (BW) within 10, 7, and 3 days. RESULTS The analyses included 6289, 5449, and 4007 patients who underwent sonographic examinations within 10, 7, and 3 days of delivery, respectively. All models yielded very high correlation coefficients (r = 0.927-0.958; R(2) = 0.859-0.918), low mean deviations between the calculated and actual BWs (6.4%-6.6% +/- 1 SD of 5.5%-5.9%), and high percentages of the calculated BW within 10% of the actual BW (78.5%-80.4%). Estimated fetal weight analyses made within 3 days of delivery yielded slightly better results than within 7 and 10 days. CONCLUSIONS The new regression formulas yielded overall similar results, with a small advantage for estimates calculated within 3 days of delivery. Further prospective studies are needed to compare the accuracy of these formulas with those used to date.
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Affiliation(s)
- Avi Ben-Haroush
- Department of Obstetrics and Gynecology, Helen Schneider's Hospital for Women, Rabin Medical Center, 49100 Petach Tikva, Israel.
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Heer IM, Kumper C, Vogtle N, Muller-Egloff S, Dugas M, Strauss A. Analysis of factors influencing the ultrasonic fetal weight estimation. Fetal Diagn Ther 2008; 23:204-10. [PMID: 18417979 DOI: 10.1159/000116742] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Accepted: 12/15/2006] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The aim of our study was the evaluation of sonographic fetal weight estimation taking into consideration 9 of the most important factors of influence on the precision of the estimation. METHODS We analyzed 820 singleton pregnancies from 22 to 42 weeks of gestational age. We evaluated 9 different factors that potentially influence the precision of sonographic weight estimation (time interval between estimation and delivery, experts vs. less experienced investigator, fetal gender, gestational age, fetal weight, maternal BMI, amniotic fluid index, presentation of the fetus, location of the placenta). Finally, we compared the results of the fetal weight estimation of the fetuses with poor scanning conditions to those presenting good scanning conditions. RESULTS Of the 9 evaluated factors that may influence accuracy of fetal weight estimation, only a short interval between sonographic weight estimation and delivery (0-7 vs. 8-14 days) had a statistically significant impact. CONCLUSION Of all known factors of influence, only a time interval of more than 7 days between estimation and delivery had a negative impact on the estimation.
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Affiliation(s)
- Ivo Markus Heer
- Department of Obstetrics and Gynecology, University Hospital Schleswig-Holstein, University Kiel, Kiel, Germany.
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Anderson NG, Jolley IJ, Wells JE. Sonographic estimation of fetal weight: comparison of bias, precision and consistency using 12 different formulae. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2007; 30:173-9. [PMID: 17557378 DOI: 10.1002/uog.4037] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
OBJECTIVES To determine the major sources of error in ultrasonographic assessment of fetal weight and whether they have changed over the last decade. METHODS We performed a prospective observational study in 1991 and again in 2000 of a mixed-risk pregnancy population, estimating fetal weight within 7 days of delivery. In 1991, the Rose and McCallum formula was used for 72 deliveries. Inter- and intraobserver agreement was assessed within this group. Bland-Altman measures of agreement from log data were calculated as ratios. We repeated the study in 2000 in 208 consecutive deliveries, comparing predicted and actual weights for 12 published equations using Bland-Altman and percentage error methods. We compared bias (mean percentage error), precision (SD percentage error), and their consistency across the weight ranges. RESULTS 95% limits of agreement ranged from - 4.4% to + 3.3% for inter- and intraobserver estimates, but were - 18.0% to 24.0% for estimated and actual birth weight. There was no improvement in accuracy between 1991 and 2000. In 2000 only six of the 12 published formulae had overall bias within 7% and precision within 15%. There was greater bias and poorer precision in nearly all equations if the birth weight was < 1,000 g. CONCLUSIONS Observer error is a relatively minor component of the error in estimating fetal weight; error due to the equation is a larger source of error. Improvements in ultrasound technology have not improved the accuracy of estimating fetal weight. Comparison of methods of estimating fetal weight requires statistical methods that can separate out bias, precision and consistency. Estimating fetal weight in the very low birth weight infant is subject to much greater error than it is in larger babies.
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Affiliation(s)
- N G Anderson
- Radiology Department, Christchurch Hospital, Christchurch, New Zealand.
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Dudley NJ. A systematic review of the ultrasound estimation of fetal weight. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2005; 25:80-9. [PMID: 15505877 DOI: 10.1002/uog.1751] [Citation(s) in RCA: 336] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVES The range and use of ultrasound fetal measurements have gradually been extended. Measurements have been combined to estimate fetal weight by mathematically based non-linear regression analysis or physically based volumetric methods. Fetal weight estimation is inaccurate, with poor sensitivity for prediction of fetal compromise. Several authors have shown the unacceptable level of intra- and interobserver variability in fetal measurement and the impact of errors on growth assessment. The aims of this study were to review the available methods and possible sources of inaccuracy. METHODS Four databases were searched for studies comparing ultrasound estimated fetal weight (EFW) with birth weight. Studies meeting the inclusion criteria evaluated 11 different methods. Errors were graphically summarized. RESULTS No consistently superior method has emerged. Volumetric methods provide some theoretical advantages. Random errors are large and must be reduced if clinical errors are to be avoided. CONCLUSIONS The accuracy of EFW is compromised by large intra- and interobserver variability. Efforts must be made to minimize this variability if EFW is to be clinically useful. This may be achieved through averaging of multiple measurements, improvements in image quality, uniform calibration of equipment, careful design and refinement of measurement methods, acknowledgment that there is a long learning curve, and regular audit of measurement quality. Further work to improve the universal validity and accuracy of fetal weight estimation formulae is also required.
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Affiliation(s)
- N J Dudley
- Medical Physics Department, Nottingham City Hospital, Hucknall Road, Nottingham NG5 1PB, UK.
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