title: Doppler study of umbilical artery in Thai fetus.
abstract: OBJECTIVE
  Create reference centile charts for Doppler study of Pulsatile index (PI), Resistance index (RI) and Systolic to Diastolic (S/D) ratio ofumbilical artery in Thai fetus throughout gestation.
  
  
  METHODS
  Six hundred fifty eight pregnant women between 13-40 weeks gestation who attended the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited. Each fetus was measured only once for the purpose of the present study. The mean and fitted centiles were estimated at each week of gestation using linear regression modeling.
  
  
  RESULTS
  Doppler study of Pulsatile index (PI), Resistance index (RI), and Systolic to Diastolic (S/D) ratio of umbilical artery were measured in 658 fetuses. The mean 95% confidence intervals for Doppler study of Pulsatile index (PI), Resistance index (RI), and Systolic to Diastolic (S/D) ratio of umbilical artery at each gestational age were fitted to estimate by linear regression models. The centile chart of this parameter was also presented.
  
  
  CONCLUSIONS
  Reference centile chart for Doppler study of Pulsatile index (PI), Resistance index (RI) and Systolic to Diastolic (S/D) ratio of umbilical artery of Thai fetuses was presented.
authors.affiliation: Department of Obstetrics and Gynaecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Anuwat
authors.initials: A
authors.lastname: Sutantawiboon
authors.forename: Saifon
authors.initials: S
authors.lastname: Chawanpaiboon
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D011247:Pregnancy; D011673:Pulsatile Flow; D013785:Thailand; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging* / Q000502:physiology