title: Limited clinical utility of midtrimester fetal morphometric percentile rankings in screening for birth weight abnormalities.
abstract: OBJECTIVE
  Our purpose was to determine whether midtrimester fetal ultrasonographic morphometric percentile rankings are sensitive screening tests for preterm labor or birth weight abnormalities.
  
  
  METHODS
  Stepwise multiple regression and chi 2 analysis were used to identify midtrimester fetal measurements predicting birth weight and gestational age. Receiver-operator characteristics curves were used to evaluate abdominal circumference percentiles as a test for large-for-gestational-age and small-for-gestational-age infants.
  
  
  RESULTS
  Extremes in abdominal circumference and head measurement percentiles were associated with large- and small-for gestational-age infants but not with preterm delivery. Abdominal circumference predicted birth weight in regression analysis; however, receiver-operator characteristic curves showed abdominal circumference percentiles to be poor screening tests for large- or small-for-gestational-age infants. The positive predictive value of 10th and 90th abdominal circumference percentiles for small- and large-for-gestational-age infants was < 20%.
  
  
  CONCLUSIONS
  Midtrimester percentile rankings offer no clear benefit in targeting fetuses with potential birth weight abnormalities or risk of preterm delivery and may provide clinically misleading information.
authors.affiliation: Department of Obstetrics and Gynecology, Wayne State University/Hutzel Hospital, Detroit, MI 48201, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Bryant
authors.forename: I
authors.initials: I
authors.lastname: Zador
authors.forename: J B
authors.initials: JB
authors.lastname: Landwehr
authors.forename: H M
authors.initials: HM
authors.lastname: Wolfe
mesh_terms: D000005:Abdomen / Q000033:anatomy & histology / Q000196:embryology; D000328:Adult; D001724:Birth Weight; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D007236:Infant, Small for Gestational Age; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012372:ROC Curve; D012044:Regression Analysis; D012680:Sensitivity and Specificity