Evaluation of the adequacy of Hadlock's reference chart for identification of fetuses with growth restriction.
OBJECTIVE
This study aimed to verify whether Hadlock's reference values for fetal weight identify fetuses below the 10th percentile in our population correctly.


METHODS
The fitness of the Hadlock reference range to our study population was tested by assessment of Z scores. We evaluated differences between the reference weight ranges proposed in our study and those recommended by Hadlock.


RESULTS
Z scores for Hadlock reference values were non-normally distributed. The difference between the 50th percentile fetal weight proposed by our study model and that proposed by Hadlock was ≤1% at GAs ≥22 weeks and 2-3% at 19-21 weeks. For the 90th percentile level, the maximum difference at GAs ≥17 weeks was 1.5%. For the 10th percentile level, the differences were 2-4% in the third trimester, reaching 8% in week 20 and 13% at a GA of 14 weeks.


CONCLUSIONS
The weight reference ranges of this study virtually overlap with the Hadlock ranges. We believe that only at lower gestational ages in the second trimester might some FGR diagnoses be missed in the population study with Hadlock's reference.
a Department of Radiology , Universidade Federal Fluminense , Niterói , Brazil.
Ana Lúcia de Freitas
ALF
Alves
a Department of Radiology , Universidade Federal Fluminense , Niterói , Brazil.
Ana Alice Vidal de
AAV
Carvalho
b Maternal and Child Department , Universidade Federal Fluminense , Niterói , Brazil.
José Antônio Bastos de
JAB
Carvalho
b Maternal and Child Department , Universidade Federal Fluminense , Niterói , Brazil.
Israel
I
Figueiredo
D000328:Adult; D003430:Cross-Sectional Studies; D018568:Crown-Rump Length; D005260:Female; D005317:Fetal Growth Retardation / Q000175:diagnosis*; D020567:Fetal Weight; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D012016:Reference Values; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal
FGR; Fetal weight; growth restriction; reference values; ultrasonography