Investigating the Reproducibility of Abdominal and Vaginal Uterine Artery Doppler Ultrasound in the First and Second Trimesters

Introduction: Elevated blood flow resistance in the uterine artery is related to the development of pre-eclampsia and fetal growth restriction, which can be evaluated with uterine artery Doppler ultrasound (UtA). However, there is a lack of studies regarding its reproducibility. Therefore, we aimed to compare the reproducibility of UtA using transvaginal (TV) and transabdominal (TA) methods in both the first and second trimesters.Materials and Method: This prospective, cross-sectional study was performed in the Prenatal Clinic at Yas Hospital, Tehran University of Medical Sciences. Inclusion criteria were gestational age between 11 to 13 weeks and 18 to 22 weeks based on crown-rump length. Both TV and TA techniques were performed by an experienced specialist in maternal and fetal medicine. Intra- and inter-observer variability of the UtA pulsatility index (UtA-PI) was evaluated using intra-class correlation coefficients.Results: This study included 400 pregnant women in the first and second trimesters of pregnancy. There was no significant difference in the mean UtA-PI measured by the operators. Intra-observer and inter-observer reproducibility of TV and TA in both the first and second trimesters, based on ICC and CCC, was moderate and poor, respectively. Intra-observer ICC ranged from 0.97 to 0.85, while the inter-observer ICC ranged from 0.93 to 0.84.Conclusion: Our results showed that intra-observer and inter-observer reproducibility of TV and TA was excellent, whereas the intra-observer and inter-observer reproducibility of TV was better. Measured UtA-PI was not influenced by the operator.