title: A modified prenatal growth assessment score for the evaluation of fetal growth in the third trimester using single and composite biometric parameters.
abstract: OBJECTIVE
  To define modified Prenatal Growth Assessment Scores (mPGAS) for single and composite biometric parameters and determine their reference ranges in normal fetuses.
  
  
  METHODS
  Nine anatomical parameters (ap) were measured and the weight estimated (EWTa, EWTb) in a longitudinal study of 119 fetuses with normal neonatal growth outcomes. Expected third trimester size trajectories, obtained from second trimester Rossavik size models, were used in calculating Percent Deviations (% Dev's) and their age-specific reference ranges in each fetus. The components of individual % Dev's values outside their reference ranges, designated +iapPGAS, -iapPGAS, were averaged to give +apPGAS and -apPGAS values for the 3rd trimester. The +iapPGAS and -iapPGAS values for different combinations of ap (c1a (HC, AC, FDL, ThC, EWTa), c1b (HC, AC, FDL, ThC, EWTb), c2 (ThC, ArmC, AVol, TVol), c3 (HC, AC, FDL, EWTa)) were then averaged to give +icPGAS and -icPGAS values at different time points or at the end of the third trimester (+cPGAS, -cPGAS). Values for iapPGAS, ic1bPGAS, and ic2PGAS were compared to their respective apPGAS or cPGAS reference ranges.
  
  
  RESULTS
  All mPGAS values had one 95% range boundary at 0.0%. Upper boundaries of 1D +apPGAS values ranged from 0.0% (HC) to +0.49% (ThC) and were +0.06%, +2.3% and +1.8% for EWT, AVol and TVol, respectively. Comparable values for -apPGAS were 0.0% (BPD, FDL, HDL), to -0.58% (ArmC), -0.13% (EWT), -0.8% (AVol), and 0.0% (TVol). The +cPGAS, 95% reference range upper boundaries varied from +0.36% (c1b) to +0.89% (c2). Comparable values for -cPGAS lower boundaries were -0.17% (c1b) to -0.43% (c2).
  
  
  CONCLUSIONS
  The original PGAS concept has now been extended to individual biometric parameters and their combinations. With the standards provided, mPGAS values can now be tested to see if detection of different types of third trimester growth problems is improved.
authors.affiliation: Department of Obstetrics and Gynecology, Baylor College of Medicine , Houston, TX , USA .
authors.forename: Russell L
authors.initials: RL
authors.lastname: Deter
authors.forename: Wesley
authors.initials: W
authors.lastname: Lee
authors.forename: Haleh
authors.initials: H
authors.lastname: Sangi-Haghpeykar
authors.forename: Adi L
authors.initials: AL
authors.lastname: Tarca
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D001699:Biometry; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005865:Gestational Age; D057238:Growth Charts; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012016:Reference Values; D016216:Ultrasonography, Prenatal
keywords: Individualized growth assessment; Rossavik models; pregnancy; size standards