title: Two-dimensional sonographic placental measurements in the prediction of small-for-gestational-age infants.
abstract: OBJECTIVE
  To determine the utility of two-dimensional (2D) sonographic placental measurements in the prediction of small-for-gestational-age (SGA) infants.
  
  
  METHODS
  The maximal diameter along the fetal surface of the placenta and the maximal placental thickness were measured at 18-24 weeks' gestation, and the measurements repeated in the orthogonal plane. 'Biometric lags' were calculated as the difference between sonographic gestational age, estimated using each of a number of fetal biometric measurements, and actual gestational age. These variables were analyzed individually and in combination as predictors of birth weight<10(th) percentile (SGA<10) and <5(th) percentile (SGA<5).
  
  
  RESULTS
  1909 singleton pregnancies were included. Mean placental diameter (SGA<10, P<0.001; SGA<5, P=0.002) and thickness (SGA<10, P<0.006; SGA<5, P=0.065) were significantly smaller in SGA pregnancies. The biometric lags were greater in SGA pregnancies, the lag in abdominal circumference (AC) being the most predictive of SGA (P<0.0001). Multivariable models were significantly predictive of both SGA<10(th) percentile (area under the receiver-operating characteristics curve (AUC) =0.7404) and <5(th) percentile (AUC=0.7204), the best fitting models including AC lag and mean placental diameter and thickness.
  
  
  CONCLUSIONS
  2D placental measurements taken in mid-gestation are significantly associated with the incidence of SGA. Biometric lags can improve the predictive ability further. These easily obtained variables should be considered in future efforts to develop a clinically useful predictive model for adverse outcome of pregnancy.
authors.affiliation: Obstetrics and Gynecology; Maternal and Child Health Research Program, Hospital of the University of Pennsylvania, Philadelphia 19104, PA, USA. schwartn@obgyn.upenn.edu)
authors.forename: N
authors.initials: N
authors.lastname: Schwartz
authors.forename: E
authors.initials: E
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Parry
mesh_terms: D000328:Adult; D004812:Epidemiologic Methods; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D009929:Organ Size / Q000502:physiology; D010920:Placenta / Q000000981:diagnostic imaging* / Q000473:pathology; D010922:Placenta Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D011247:Pregnancy; D016216:Ultrasonography, Prenatal / Q000379:methods