Figure 4b. Hydronephrosis of pregnancy in a 25-year-old woman during the third trimester. (a) Coronal static thick-slab MR urogram shows severe right hydronephrosis (arrowhead). (b) Sagittal half-Fourier RARE image obtained through the right kidney shows tapering of the ureter (arrow) proximal to the site of compression by the uterus.