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Ultrasound diagnosis of fetal macrosomia: a comparison of weight prediction models using computer simulation
Author(s) -
Mongelli M.,
Benzie R.
Publication year - 2005
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.1989
Subject(s) - fetal macrosomia , medicine , gestational age , fetal weight , fetus , gestation , ultrasound , obstetrics , birth weight , pregnancy , radiology , gestational diabetes , biology , genetics
Objective To assess the frequency of the diagnosis of macrosomia in relation to differing weight estimation formulae in unselected pregnancies. Methods Computer modeling techniques were employed. Computer modeling software generated correlated fetal biometry measurements according to published British standards, from 37 to 41 weeks' gestation. For each set of measurements, estimated fetal weights were obtained by a panel of 18 ultrasound weight formulae. The diagnosis of macrosomia was made if the fetal weight estimate was greater than 4500 g. Cohorts of 5000 pregnancies for each week of gestation were studied. Results The frequency of diagnosis of macrosomia increased progressively with advancing gestational age, with large increases between 40 and 41 weeks. The type of weight estimation formula had a profound influence on the frequency of diagnosis of macrosomia. Five of the formulae tested almost never returned a weight estimate greater than 4500 g. Three formulae yielded false positive rates in excess of 15%. The Hadlock group of formulae yielded frequencies of 0.3% to 14.6%. Conclusions Most formulae tend to over‐diagnose macrosomia at term. Intervention rates for suspected fetal macrosomia may be influenced by gestational age at the time of scan and the type of fetal weight estimation formula in use. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.