title: Reference charts of fetal biometric parameters in 31,476 Brazilian singleton pregnancies.
abstract: OBJECTIVE
  The purpose of this study was to establish reference charts of fetal biometric parameters measured by 2-dimensional sonography in a large Brazilian population.
  
  
  METHODS
  A cross-sectional retrospective study was conducted including 31,476 low-risk singleton pregnancies between 18 and 38 weeks' gestation. The following fetal parameters were measured: biparietal diameter, head circumference, abdominal circumference, femur length, and estimated fetal weight. To assess the correlation between the fetal biometric parameters and gestational age, polynomial regression models were created, with adjustments made by the determination coefficient (R(2)).
  
  
  RESULTS
  The means ± SDs of the biparietal diameter, head circumference, abdominal circumference, femur length, and estimated fetal weight measurements at 18 and 38 weeks were 4.2 ± 2.34 and 9.1 ± 4.0 cm, 15.3 ± 7.56 and 32.3 ± 11.75 cm, 13.3 ± 10.42 and 33.4 ± 20.06 cm, 2.8 ± 2.17 and 7.2 ± 3.58 cm, and 256.34 ± 34.03 and 3169.55 ± 416.93 g, respectively. Strong correlations were observed between all fetal biometric parameters and gestational age, best represented by second-degree equations, with R(2) values of 0.95, 0.96, 0.95, 0.95, and 0.95 for biparietal diameter, head circumference, abdominal circumference, femur length, and estimated fetal weight.
  
  
  CONCLUSIONS
  Fetal biometric parameters were determined for a large Brazilian population, and they may serve as reference values in cases with a high risk of intrauterine growth disorders.
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.).
authors: Edward
authors: E
authors: Araujo Júnior
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.).
authors: Eduardo Félix
authors: EF
authors: Martins Santana
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.).
authors: Wellington P
authors: WP
authors: Martins
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.). araujojred@terra.com.br.
authors: Julio Elito
authors: JE
authors: Júnior
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.).
authors: Rodrigo
authors: R
authors: Ruano
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.).
authors: Claudio Rodrigues
authors: CR
authors: Pires
authors: Referral Center for Teaching of Diagnostic Imaging, São Paulo, Brazil (E.A.J., C.R., S.M.Z.F.); Department of Obstetrics, Paulista School of Medicine, São Paulo Federal University, São Paulo, Brazil (E.A.J., E.F.M.S., J.E.J.); Department of Obstetrics and Gynecology, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, Brazil (W.P.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (W.P.M.); and Department of Gynecology and Obstetrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas USA (R.R.).
authors: Sebastião Marques Zanforlin
authors: SM
authors: Filho
mesh_terms: D000293:Adolescent; D000328:Adult; D001699:Biometry; D001938:Brazil; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000196:embryology; D020567:Fetal Weight; D005333:Fetus / Q000033:anatomy & histology*; D006257:Head / Q000196:embryology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D055815:Young Adult
keywords: Brazilian population; fetal biometric parameters; obstetric ultrasound; reference charts; sonography