Prediction of fetal macrosomia: effect of sonographic fetal weight-estimation model and threshold used
Article first published online: 24 MAY 2011
Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound in Obstetrics & Gynecology
Volume 38, Issue 1, pages 74–81, July 2011
How to Cite
Melamed, N., Yogev, Y., Meizner, I., Mashiach, R., Pardo, J. and Ben-Haroush, A. (2011), Prediction of fetal macrosomia: effect of sonographic fetal weight-estimation model and threshold used. Ultrasound Obstet Gynecol, 38: 74–81. doi: 10.1002/uog.8930
- Issue published online: 28 JUN 2011
- Article first published online: 24 MAY 2011
- Accepted manuscript online: 12 JAN 2011 09:43AM EST
- Manuscript Accepted: 5 JAN 2011
To compare the accuracy of 21 sonographic fetal weight-estimation models and abdominal circumference (AC) as a single measure for the prediction of fetal macrosomia (> 4000 g) using either fixed or optimal model-specific thresholds.
A total of 4765 sonographic weight estimations performed within 3 days prior to delivery were analyzed. The predictive accuracy of 21 published sonographic fetal weight-estimation models was calculated using three different thresholds: a fixed threshold of 4000 g; a model-specific threshold obtained from the inflexion point of the receiver–operating characteristics (ROC) curve; and a model-specific threshold associated with the highest overall accuracy. Cluster analysis was used to determine whether a certain combination of fetal biometric indices is associated with a higher predictive accuracy than others.
For a fixed threshold of > 4000 g, there was considerable variation among the models in sensitivity (range, 13.6–98.5%) and specificity (range, 63.6–99.8%) for fetal macrosomia. Use of the threshold derived from the inflexion point of the ROC curve decreased the intermodel variation to a minimum (sensitivity, 84.4–91.4%; and specificity, 79.5–86.3%). Even when this optimal model-specific threshold was applied, models based on three to four biometric indices were more accurate than were models based on only two biometric indices or on AC as a single measure (P = 0.03).
Sonographic fetal weight-estimation models based on three to four biometric indices appear to be more accurate than are models based on two indices or on AC as a single measure, for the diagnosis of macrosomia. In these cases, the use of an optimal, model-specific threshold is associated with a higher degree of accuracy than is the uniform use of a fixed threshold of an estimated weight of > 4000 g. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.