Accuracy and precision of sonographic fetal weight estimation in Sweden
Abstract Introduction Fetal growth assessment by ultrasound is an essential part of modern obstetric care. The formula by Persson and Weldner for estimated fetal weight (EFW), used in Sweden since decades, has not yet been evaluated. The objective of this study was to evaluate accuracy and precision...
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Wiley
2023-06-01
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| Series: | Acta Obstetricia et Gynecologica Scandinavica |
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| Online Access: | https://doi.org/10.1111/aogs.14554 |
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| author | Linda Lindström Sven Cnattingius Ove Axelsson Michaela Granfors |
| author_facet | Linda Lindström Sven Cnattingius Ove Axelsson Michaela Granfors |
| author_sort | Linda Lindström |
| collection | DOAJ |
| description | Abstract Introduction Fetal growth assessment by ultrasound is an essential part of modern obstetric care. The formula by Persson and Weldner for estimated fetal weight (EFW), used in Sweden since decades, has not yet been evaluated. The objective of this study was to evaluate accuracy and precision of the formula by Persson and Weldner, and to compare it to two other formulae using biparietal diameter instead of head circumference. Material and methods The study population consisted of 31 521 singleton pregnancies delivered at 22+0 gestational weeks or later, with an ultrasound EFW performed within 2 days before delivery, registered in the Swedish Pregnancy Register between 2014 and 2021. Fetal biometric ultrasound measurements were used to calculate EFW according to the formulae by Persson and Weldner, Hadlock 2 and Shepard. Bland–Altman analysis, systematic error (mean percentage error), random error (standard deviation [SD] of mean percentage error), proportion of weight estimates within ±10% of birthweight, and proportion with underestimated and overestimated weight was calculated. Moreover, calculations were made after stratification into small, appropriate, and large for gestational age (SGA, AGA and LGA), respectively, and gestational age at examination. Results For the formula by Persson and Weldner, MPE was −2.7 (SD 8.9) and the proportion of EFW within ±10% from actual birthweight was 76.0%. MPE was largest for fetuses estimated as severe SGA (<3rd percentile, −5.4) and for the most preterm fetuses (<24 weeks, −5.4). For Hadlock 2 and Shepard's formulae, MPE were 3.9 (SD 8.9) and 3.4 (SD 9.7), respectively, and the proportions of EFW within ±10% from actual birthweight were 69.4% and 67.1%, respectively. MPE was largest for fetuses estimated as severe LGA (>97th percentile), 7.6 and 9.4, respectively. Conclusions The recommended Swedish formula by Persson and Weldner is generally accurate for fetal weight estimation. The systematic underestimation of EFW and random error is largest in extreme preterm and estimated SGA‐fetuses, which is of importance in clinical decision making. The accuracy of EFW with the formula by Persson and Weldner is as good as or better than Hadlock 2 and Shepard's formulae. |
| format | Article |
| id | doaj-art-4ac9050ee3e04c7d96295f7a8dacf4e6 |
| institution | DOAJ |
| issn | 0001-6349 1600-0412 |
| language | English |
| publishDate | 2023-06-01 |
| publisher | Wiley |
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| series | Acta Obstetricia et Gynecologica Scandinavica |
| spelling | doaj-art-4ac9050ee3e04c7d96295f7a8dacf4e62025-08-20T03:22:21ZengWileyActa Obstetricia et Gynecologica Scandinavica0001-63491600-04122023-06-01102669970710.1111/aogs.14554Accuracy and precision of sonographic fetal weight estimation in SwedenLinda Lindström0Sven Cnattingius1Ove Axelsson2Michaela Granfors3Division of Clinical Epidemiology, Department of Medicine (Solna) Karolinska Institutet Stockholm SwedenDivision of Clinical Epidemiology, Department of Medicine (Solna) Karolinska Institutet Stockholm SwedenDepartment of Women's and Children's Health Uppsala University Uppsala SwedenDivision of Clinical Epidemiology, Department of Medicine (Solna) Karolinska Institutet Stockholm SwedenAbstract Introduction Fetal growth assessment by ultrasound is an essential part of modern obstetric care. The formula by Persson and Weldner for estimated fetal weight (EFW), used in Sweden since decades, has not yet been evaluated. The objective of this study was to evaluate accuracy and precision of the formula by Persson and Weldner, and to compare it to two other formulae using biparietal diameter instead of head circumference. Material and methods The study population consisted of 31 521 singleton pregnancies delivered at 22+0 gestational weeks or later, with an ultrasound EFW performed within 2 days before delivery, registered in the Swedish Pregnancy Register between 2014 and 2021. Fetal biometric ultrasound measurements were used to calculate EFW according to the formulae by Persson and Weldner, Hadlock 2 and Shepard. Bland–Altman analysis, systematic error (mean percentage error), random error (standard deviation [SD] of mean percentage error), proportion of weight estimates within ±10% of birthweight, and proportion with underestimated and overestimated weight was calculated. Moreover, calculations were made after stratification into small, appropriate, and large for gestational age (SGA, AGA and LGA), respectively, and gestational age at examination. Results For the formula by Persson and Weldner, MPE was −2.7 (SD 8.9) and the proportion of EFW within ±10% from actual birthweight was 76.0%. MPE was largest for fetuses estimated as severe SGA (<3rd percentile, −5.4) and for the most preterm fetuses (<24 weeks, −5.4). For Hadlock 2 and Shepard's formulae, MPE were 3.9 (SD 8.9) and 3.4 (SD 9.7), respectively, and the proportions of EFW within ±10% from actual birthweight were 69.4% and 67.1%, respectively. MPE was largest for fetuses estimated as severe LGA (>97th percentile), 7.6 and 9.4, respectively. Conclusions The recommended Swedish formula by Persson and Weldner is generally accurate for fetal weight estimation. The systematic underestimation of EFW and random error is largest in extreme preterm and estimated SGA‐fetuses, which is of importance in clinical decision making. The accuracy of EFW with the formula by Persson and Weldner is as good as or better than Hadlock 2 and Shepard's formulae.https://doi.org/10.1111/aogs.14554biparietal diameterestimated fetal weightfetal growthgestational agehead circumferencePersson and Weldner |
| spellingShingle | Linda Lindström Sven Cnattingius Ove Axelsson Michaela Granfors Accuracy and precision of sonographic fetal weight estimation in Sweden Acta Obstetricia et Gynecologica Scandinavica biparietal diameter estimated fetal weight fetal growth gestational age head circumference Persson and Weldner |
| title | Accuracy and precision of sonographic fetal weight estimation in Sweden |
| title_full | Accuracy and precision of sonographic fetal weight estimation in Sweden |
| title_fullStr | Accuracy and precision of sonographic fetal weight estimation in Sweden |
| title_full_unstemmed | Accuracy and precision of sonographic fetal weight estimation in Sweden |
| title_short | Accuracy and precision of sonographic fetal weight estimation in Sweden |
| title_sort | accuracy and precision of sonographic fetal weight estimation in sweden |
| topic | biparietal diameter estimated fetal weight fetal growth gestational age head circumference Persson and Weldner |
| url | https://doi.org/10.1111/aogs.14554 |
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