title: Prediction of small-for-gestational-age neonate by third-trimester fetal biometry and impact of ultrasound-delivery interval.
abstract: OBJECTIVE
  To compare third-trimester ultrasound screening methods to predict small-for-gestational age (SGA), and to evaluate the impact of the ultrasound-delivery interval on screening performance.
  
  
  METHODS
  In this prospective study, data were collected from a multicenter singleton cohort study investigating the links between various exposures during pregnancy with birth outcome and later health in children. We included women, recruited in the first trimester, who had complete outcome data and had undergone third-trimester ultrasound examination. Demographic, clinical and biological variables were also collected from both parents. We compared prediction of delivery of a SGA neonate (birth weight < 10thpercentile) by the following methods: abdominal circumference (AC) Z-score based on Hadlock curves (Hadlock AC), on INTERGROWTH-21stProject curves (Intergrowth AC) and on Salomon curves (Salomon AC); estimated fetal weight (EFW) Z-score based on Hadlock curves (Hadlock EFW) and on customized curves from Gardosi (Gardosi EFW); and fetal growth velocity based on change in AC between second and third trimesters (FGVAC). We also assessed the following ultrasound-delivery intervals: ≤ 4 weeks, ≤ 6 weeks and ≤ 10 weeks.
  
  
  RESULTS
  Third-trimester ultrasound was performed in 1805 patients with complete outcome data, of whom 158 (8.8%) delivered a SGA neonate. Ultrasound examination was at a median gestational age of 32 (interquartile range, 31-33) weeks. The ultrasound-delivery interval was ≤ 4 weeks in 17.2% of cases, ≤ 6 weeks in 48.1% of cases and ≤ 10 weeks in 97.3% of cases. Areas under the receiver-operating characteristics curve (AUC) were 0.772 for Salomon AC, 0.768 for Hadlock EFW, 0.766 for Hadlock AC, 0.765 for Intergrowth AC, 0.708 for Gardosi EFW and 0.674 for FGVAC (all P < 0.0001). The screening method with the highest AUC for an ultrasound-delivery interval ≤ 4 weeks was Salomon AC (AUC, 0.856), ≤ 6 weeks was Hadlock AC (AUC, 0.824) and ≤ 10 weeks was Salomon AC (AUC, 0.780). At a fixed 10% false-positive rate, the best detection rates were 60.0%, 54.1% and 42.1% for intervals ≤ 4, ≤ 6 and ≤ 10 weeks, respectively.
  
  
  CONCLUSIONS
  Third-trimester ultrasound measurements provide poor to moderate prediction of SGA. A shorter ultrasound-delivery interval provides better prediction than does a longer interval. Further studies are needed to test the effect of including maternal or biological characteristics in SGA screening. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.|Department of Obstetrics and Gynaecology, CHU Saint-Etienne, Université Jean Monnet, Saint-Etienne, France.
authors.forename: Q
authors.initials: Q
authors.lastname: Reboul
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Delabaere
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Z C
authors.initials: ZC
authors.lastname: Luo
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: A-M
authors.initials: AM
authors.lastname: Nuyt
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Saint-Etienne, Université Jean Monnet, Saint-Etienne, France.
authors.forename: C
authors.initials: C
authors.lastname: Chauleur
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: W
authors.initials: W
authors.lastname: Fraser
authors.affiliation: Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Audibert
mesh_terms: D000328:Adult; D001699:Biometry / Q000379:methods*; D001724:Birth Weight; D005260:Female; D005317:Fetal Growth Retardation / Q000175:diagnosis*; D020567:Fetal Weight; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012372:ROC Curve; D016216:Ultrasonography, Prenatal / Q000379:methods*
keywords: Hadlock; SGA; fetal growth; ultrasound