title: Effect of amniotic fluid volume on ultrasonic fetal weight estimation.
abstract: We evaluated the relationship between the amniotic fluid index and the accuracy of fetal weight estimation using ultrasonography. Six hundred and sixty-four patients, between 20 and 42 weeks' gestational age, who were delivered within 1 week of a sonographic examination were studied. Five formulas for estimating fetal weight also were studied. Systematic and random errors in predicting birth weight were analyzed relative to birth weight and amniotic fluid index. The accuracy of sonographic fetal weight estimation was independent of amniotic fluid index across all gestational ages and birth weights. Each of the five formulas had similar error percentages, and no significant differences were detected. Predicted fetal weight was significantly underestimated with each of the formulas studied, a finding that was also independent of birth weight and amniotic fluid index. We conclude that ultrasonography can be used reliably to estimate fetal weight in patients with altered amniotic fluid volumes.
authors.affiliation: Department of Obstetrics and Gynecology, University of Illinois, Chicago 60612-7313, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Meyer
authors.forename: G E
authors.initials: GE
authors.lastname: Font
authors.forename: D W
authors.initials: DW
authors.lastname: Gauthier
authors.forename: T D
authors.initials: TD
authors.lastname: Myles
authors.forename: A
authors.initials: A
authors.lastname: Bieniarz
authors.forename: A
authors.initials: A
authors.lastname: Rodriguez
mesh_terms: D000653:Amniotic Fluid; D000886:Anthropometry; D001724:Birth Weight; D001835:Body Weight; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal