Reference Range and Characteristic of Uterine Artery Doppler in Pregnant Thai Women at 11-13+6 Gestational Weeks
Orapin Rattanapuntamanee MD*, Boonchai Uerpairojkit MD*
Affiliation : * Department of Obstetrics and Genecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
Objective : To determine uterine artery pulsatility index (PI) and to describe the characteristic of uterine artery Doppler
velocimetry in pregnant Thai women at 11-13+6 gestational weeks.
Material and Method: Between July 29, 2010 and September 30, 2010, 150 normal pregnant women at 11-13+6 weeks of
gestation who were attending at the antenatal care clinic, Department of Obstetrics and Genecology, Faculty of Medicine,
Chulalongkorn University were recruited. Pulsatility index (PI) of the uterine artery was measured and mean PI was
calculated and plotted against gestational age. Presence or absence of uterine notching in relation to laterality was also noted.
Results : The mean + SD uterine artery PI was 1.73 + 0.42. When segregated for gestation age, uterine artery PI was
1.78 + 0.41 at 11 weeks, 1.72 + 0.41 at 12 weeks, and 1.66 + 0.43 at 13 weeks’gestation. The uterine artery PI was 1.84 + 0.37
with presence of notching and was 1.59 + 0.43 without notching. The uterine artery notching was presented in 29 (19.3%),
24 (16%), and 27 (18%) of the patients at 11, 12, and 13 weeks respectively. The uterine artery notching was absent in
27 (18%), 23(15.3%), and 20(13.3%) of patients at 11, 12, and 13 weeks respectively. Thirty-nine patients (26%) demonstrated
unilateral notch, 12 (8%) of the patients demonstrated ipsilateral notch, 19 patients (12.7%) demonstrated contralateral
notch, and eight (5.3%) demonstrated unilateral notch with central placenta.
Conclusion : Normal reference range and characteristics of uterine artery Doppler velocimetry in the presented population
was established. This may serve as a basis for a future study in patients with abnormal placental function.
Keywords : Early diastolic notching, First trimester, Pulsatility index, Uterine artery Doppler
