Colour Doppler evaluation of ureteral jets in normal second and third trimester pregnancy: effect of patient position

The study was designed to investigate the effect of patient position on the detection of ureteral jets in normal pregnancy. The number of jets was recorded for 1 min using colour Doppler ultrasound in 26 healthy asymptomatic gravid women between 16 weeks and 34 weeks gestation. Each patient was examined in the supine position and in both the right and left lateral decubitus positions. Ureteral jets were present on at least one side in 24 patients in the supine position compared with 26 women in the lateral decubitus position. 13 (54%) of the 24 patients in whom jets were seen in the supine position had jets on only one side. A mean of 1.80 jets x min(-1) was detected on the right side and 3.23 jets x min(-1) on the left (p=0.046) in the supine position. In the contralateral decubitus position, jets were detected on the right side in 22 (85%) women and on the left in 25 (96%) women. A mean of 3.07 jets x min(-1) was detected on the right and 4.15 jets x min(-1) on the left. The difference in the frequency of ureteral jets between the supine and lateral decubitus positions was significant (p=0.004 for the right; p=0.011 for the left). However, the difference in the detection rate was significant on only the right side (p=0.016 for the right; p=0.063 for the left). 10 (77%) of 13 patients in whom unilateral absence of ureteral jets was noted had detectable jets in the lateral decubitus position. Our findings demonstrated the utility of the lateral decubitus position in the evaluation of ureters suspicious for obstruction. However, caution is still recommended in diagnosing ureteral obstruction if jets are persistently absent after this manoeuvre.