title: PP071. Evaluation of maternal-fetal doppler parameters and of whole blood nitrite throughout gestation.
abstract: BACKGROUND
  The Doppler method is extensively applied today for the evaluation of pregnancies with involvement of the uteroplacental blood flow. Although increased nitric oxide (NO) formation plays an important role in regulation of systemic vascular resistance during pregnancy, growing evidence indicates that reduced NO formation is associated with hypertensive disorders of pregnancy, especially preeclampsia.
  
  
  OBJECTIVE
  The studies were to assess the maternal and fetal Doppler parameters and to determine the whole blood nitrite levels during pregnancy.
  
  
  METHODS
  Thirty-three healthy pregnant women were evaluated during the first (11-14 weeks), second (20-24 weeks) and third trimesters (34-36 weeks) of pregnancy. The maternal (uterine arteries) and fetal (cerebral and umbilical arteries) vessels were evaluated by Doppler velocimetry. venous blood was collected(15mL) for the determination of plasma nitrite by chemiluminescence.
  
  
  RESULTS
  Regarding the Doppler parameters of the uterine arteries the mean pulsatility index was 1.73, 1.06 and 0.73 in the first, second and third trimesters of pregnancy, respectively. Fetal Doppler showed a mean resistance index of 0.82 and 0.81 for the middle cerebral artery, 0.73 and 0.60 for the umbilical artery in the second and third trimesters, respectively. The mean plasma nitrite concentration was 189.10, 178.28 and 199.57 nmol/ml in the first, second and third trimesters of pregnancy, respectively.
  
  
  CONCLUSIONS
  The study demonstrated that a fall in flow resistance occurs in the uteroplacental vessels without changes in plasma nitrite concentrations during pregnancy.
authors.affiliation: Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: R C
authors.initials: RC
authors.lastname: Cavalli
authors.affiliation: Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: S D
authors.initials: SD
authors.lastname: Jorge Neto
authors.affiliation: PG, IEP-SCBH, Belo Horizonte, Ribeirão Preto, Brazil.
authors.forename: V C
authors.initials: VC
authors.lastname: Sandrim
authors.affiliation: Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: J S
authors.initials: JS
authors.lastname: Machado
authors.affiliation: Farmacology, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: J T
authors.initials: JT
authors.lastname: Sertório
authors.affiliation: Farmacology, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: A C T
authors.initials: AC
authors.lastname: Palei
authors.affiliation: Farmacology, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: Amaral
authors.affiliation: Farmacology, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: J E Tanus
authors.initials: JE
authors.lastname: Santos
authors.affiliation: Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto - University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Duarte