Journal of the Korean Society of Medical Ultrasound (대한초음파의학회지), Vol.20(3) : 193~198, 2001
Journal of the Korean Society of Medical Ultrasound (대한초음파의학회지)
PURPOSE : Our purpose was to investigate the relation between the vascular resistance of uterine artery and placental location, and to establish the reference value of Doppler index in uterine artery by placental location. MATERIALS and METHODS : Placental location and flow velocity waveforms of both uterine arteries in 7,016 pregnant women after 18 weeks gestation were examined using color Doppler ultrasonography. Placental location was classified as central and lateral placenta and the uterine artery with lateral placenta were divided into ipsilateral uterine artery(same side of the placenta) and contralateral uterine artery(opposite side of the placenta). The uterine artery with central placenta was classified as the central uterine artery. Systolic-Diastolic ratio(S/D ratio) of uterine arteries by gestational weeks were calculated and campared with the placental location and perinatal outcomes. RESULTS : In the lateral placenta group, the S/D ratio of the contralateral uterine artery was higher than the ipsilateral one(mean=2.08+0.34 Vs 1.89+0.34, p=0.0001). S/D ratio of the uterine artery decreased during second trimester and the ratio after 27 weeks was a tendency to have a constant values(ipsilateral: 1.85+0.34, central: 1.96+0.40, contralateral: 2.01+0.54). CONCLUSION : S/D ratio of the uterine artery was affected by placental location. So when we evaluate Doppler spectrum of uterine artery, placental location should be considered and we established the reference value of Doppler index of uterine artery by placental location.