title: Second-Trimester 3-Dimensional Placental Sonography as a Predictor of Small-for-Gestational-Age Birth Weight.
abstract: OBJECTIVE
  We previously reported the association between first-trimester 3-dimensional (3D) placental measurements and small-for-gestational-age (SGA) neonates. In this study, we sought to determine whether second-trimester measurements further contribute to the antenatal detection of SGA and preeclampsia.
  
  
  METHODS
  We prospectively collected 3D sonographic volume sets and uterine artery pulsatility indices of singleton pregnancies at 18 to 24 weeks. Placental volume, placental quotient (placental volume/gestational age), mean placental diameter and chorionic diameter, placental morphologic index (mean placental diameter/placental quotient), placental chorionic index (mean chorionic diameter/placental quotient), and placental growth (volume per week) were assessed and evaluated as predictors of SGA and preeclampsia as a composite and alone.
  
  
  RESULTS
  Of 373 pregnancies, the composite outcome occurred in 67 (18.0%): 36 (9.7%) manifested SGA alone; 27 (7.2%) developed preeclampsia alone, and 4 (1.1%) developed both. The placental volume, placental quotient, mean placental diameter, mean chorionic diameter, and volume per week were significantly smaller, whereas the placental morphologic index and chorionic index were significantly larger in pregnancies with the composite outcome (P < .01). Further analyses revealed that the significant associations with placental parameters were limited to the SGA outcome. Each placental measure remained significantly associated with SGA after adjusting for confounders. The mean uterine artery pulsatility index was not associated with either outcome. Placental parameters were moderately predictive of SGA, with adjusted areas under the curve ranging from 0.72 to 0.76. Sensitivity for detection of SGA ranged from 32.5% to 45.0%, with positive predictive values ranging from 17.3% to 22.7%.
  
  
  CONCLUSIONS
  Second-trimester 3D placental measurements can identify pregnancies at risk of SGA. However, there appears to be no significant improvement compared to those obtained in the first trimester.
authors.affiliation: Department of Obstetrics and Gynecology, Maternal and Child Health Research Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA.
authors.forename: Hayley S
authors.initials: HS
authors.lastname: Quant
authors.affiliation: Department of Biostatistics and Epidemiology, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA.
authors.forename: Mary D
authors.initials: MD
authors.lastname: Sammel
authors.affiliation: Department of Obstetrics and Gynecology, Maternal and Child Health Research Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Parry
authors.affiliation: Department of Obstetrics and Gynecology, Maternal and Child Health Research Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA.
authors.forename: Nadav
authors.initials: N
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007236:Infant, Small for Gestational Age / Q000502:physiology*; D010920:Placenta / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*
keywords: 3-dimensional sonography; adverse pregnancy outcomes; fetal growth restriction; obstetric ultrasound; placenta; uterine artery Doppler sonography