title: Non-influence of fetal gender on ductus venosus Doppler flow in the first trimester.
abstract: OBJECTIVE
  Recent findings have suggested that ductus venosus blood flow may be influenced by fetal gender. The aim of this study was to investigate further the influence of fetal gender on ductus venosus Doppler flow in the first trimester.
  
  
  METHODS
  This was a cross-sectional and retrospective study performed between January 1998 and January 2003. A total of 932 fetuses at between 10 and 14 weeks' gestation were included. The following inclusion criteria were used: singleton gestation; crown-rump length between 39 and 84 mm; and absence of fetal anomalies. The following variables of the ductus venosus were evaluated: peak velocity during ventricular systole (S-wave) and diastole (D-wave); nadir during atrial contraction in late diastole (A-wave); pulsatility index for veins (PIV); peak velocity index for veins (PVIV); and time-averaged maximum velocity (TAMXV).
  
  
  RESULTS
  Four hundred and forty-eight (48.1%) female and 484 (51.9%) male fetuses were included in the study. Comparing males and females at between 10 and 14 weeks' gestation, there was no statistically significant difference in S-wave, D-wave, A-wave, PIV, PVIV or TAMXV.
  
  
  CONCLUSIONS
  Our study suggests that fetal gender does not influence ductus venosus blood flow in the first trimester.
authors.affiliation: Serviço de Medicina Fetal-Eccos-Clinica da Imagem, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
authors.forename: L S
authors.initials: LS
authors.lastname: Teixeira
authors.forename: J
authors.initials: J
authors.lastname: Leite
authors.forename: M J B
authors.initials: MJ
authors.lastname: Castro Viegas
authors.forename: M M L
authors.initials: MM
authors.lastname: Faria
authors.forename: M C
authors.initials: MC
authors.lastname: Pires
authors.forename: H C
authors.initials: HC
authors.lastname: Teixeira
authors.forename: R C
authors.initials: RC
authors.lastname: Teixeira
authors.forename: H
authors.initials: H
authors.lastname: Pettersen
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D003430:Cross-Sectional Studies; D018568:Crown-Rump Length; D005260:Female; D006801:Humans; D008102:Liver Circulation / Q000502:physiology*; D008297:Male; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012039:Regional Blood Flow; D012189:Retrospective Studies; D012737:Sex Factors; D018615:Ultrasonography, Doppler, Color; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal; D014471:Umbilical Veins / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology*; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology*