title: Single and Serial Fetal Biometry to Detect Preterm and Term Small- and Large-for-Gestational-Age Neonates: A Longitudinal Cohort Study.
abstract: OBJECTIVE
  To assess the value of single and serial fetal biometry for the prediction of small- (SGA) and large-for-gestational-age (LGA) neonates delivered preterm or at term.
  
  
  METHODS
  A cohort study of 3,971 women with singleton pregnancies was conducted from the first trimester until delivery with 3,440 pregnancies (17,334 scans) meeting the following inclusion criteria: 1) delivery of a live neonate after 33 gestational weeks and 2) two or more ultrasound examinations with fetal biometry parameters obtained at ≤36 weeks. Primary outcomes were SGA (<5th centile) and LGA (>95th centile) at birth based on INTERGROWTH-21st gender-specific standards. Fetus-specific estimated fetal weight (EFW) trajectories were calculated by linear mixed-effects models using data up to a fixed gestational age (GA) cutoff (28, 32, or 36 weeks) for fetuses having two or more measurements before the GA cutoff and not already delivered. A screen test positive for single biometry was based on Z-scores of EFW at the last scan before each GA cut-off so that the false positive rate (FPR) was 10%. Similarly, a screen test positive for the longitudinal analysis was based on the projected (extrapolated) EFW at 40 weeks from all available measurements before each cutoff for each fetus.
  
  
  RESULTS
  Fetal abdominal and head circumference measurements, as well as birth weights in the Detroit population, matched well to the INTERGROWTH-21st standards, yet this was not the case for biparietal diameter (BPD) and femur length (FL) (up to 9% and 10% discrepancy for mean and confidence intervals, respectively), mainly due to differences in the measurement technique. Single biometry based on EFW at the last scan at ≤32 weeks (GA IQR: 27.4-30.9 weeks) had a sensitivity of 50% and 53% (FPR = 10%) to detect preterm and term SGA and LGA neonates, respectively (AUC of 82% both). For the detection of LGA using data up to 32- and 36-week cutoffs, single biometry analysis had higher sensitivity than longitudinal analysis (52% vs 46% and 62% vs 52%, respectively; both p<0.05). Restricting the analysis to subjects with the last observation taken within two weeks from the cutoff, the sensitivity for detection of LGA, but not SGA, increased to 65% and 72% for single biometry at the 32- and 36-week cutoffs, respectively. SGA screening performance was higher for preterm (<37 weeks) than for term cases (73% vs 46% sensitivity; p<0.05) for single biometry at ≤32 weeks.
  
  
  CONCLUSIONS
  When growth abnormalities are defined based on birth weight, growth velocity (captured in the longitudinal analysis) does not provide additional information when compared to the last measurement for predicting SGA and LGA neonates, with both approaches detecting one-half of the neonates (FPR = 10%) from data collected at ≤32 weeks. Unlike for SGA, LGA detection can be improved if ultrasound scans are scheduled as close as possible to the gestational-age cutoff when a decision regarding the clinical management of the patient needs to be made. Screening performance for SGA is higher for neonates that will be delivered preterm.
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.|Department of Computer Science, Wayne State University College of Engineering, Detroit, Michigan, United States of America.
authors: Adi L
authors: http://orcid.org/0000-0003-1712-7588
authors: AL
authors: Tarca
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Edgar
authors: E
authors: Hernandez-Andrade
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Hyunyoung
authors: H
authors: Ahn
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Maynor
authors: M
authors: Garcia
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.
authors: Zhonghui
authors: Z
authors: Xu
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.|Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, Michigan, United States of America.
authors: Steven J
authors: SJ
authors: Korzeniewski
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Homam
authors: H
authors: Saker
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Tinnakorn
authors: T
authors: Chaiworapongsa
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Sonia S
authors: SS
authors: Hassan
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
authors: Lami
authors: L
authors: Yeo
authors: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, Michigan, United States of America.|Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, Michigan, United States of America.|Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, United States of America.|Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America.
authors: Roberto
authors: R
authors: Romero
mesh_terms: D000328:Adult; D001699:Biometry / Q000379:methods*; D001724:Birth Weight / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology; D020567:Fetal Weight / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000502:physiology*; D008137:Longitudinal Studies; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000502:physiology; D018570:Risk Assessment; D047929:Term Birth / Q000502:physiology*; D016216:Ultrasonography, Prenatal / Q000379:methods; D055815:Young Adult