Reference Centile Charts for Fetal Umbilical Artery Doppler Velocimetry Waveform of Thai Fetuses

Abstract

Objective To create reference centile charts for fetal umbilical arteries Dopper velocimetry wave forms of Thai fetuses.  

Subjects and Methods A total of 621 pregnant women, who attended the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited between 12 and 41 weeks of gestation. Each fetus was measured only once for the purpose of this study. Using a Duplex pulsed wave Doppler Ultrasound with a 3.5 MHz convex transducer, we measured systolic/diastolic ratio (S/ D ratio), pulsatilily index (PI), and resistance index (RI) of fetal umbilical arteries. The mean and standard deviation (SD) of each Doppler indices were estimated at each week of gestation using stepwise linear regression modeling.

Results A total of 617 fetuses were measured for systolic/diastolic ratio (S/D ratio), pulsatilily index (Pl), and resistance index (RI) of fetal umbilical arteries. Regression models were fitted to estimate the mean and standard deviation for each parameter at each gestational age. The centile charts of each parameter were derived from regression equations and are presented.

Conclusion We have presented reference centile charts for systolic/diastolic ratio (S/D ratio), pulsatilily index (PI), and resistance index (RI) of fetal umbilical arteries of Thai fetuses.