Physiologic hydronephrosis of pregnancy in a female at 24 weeks gestation

(A) Transabdominal longitudinal color Doppler view of the right kidney in a female 24 weeks pregnant with right flank pain. There is moderate to severe right hydronephrosis. The ureter (not shown) was seen to the level of the pelvic brim. No stones were visualized. The left kidney was not distended. The color Doppler used in the kidney is to demonstrate that the dilated cystic spaces are the collecting system and not dilated vessels.
(B) Transabdominal transverse image of a full bladder shows bilateral ureteral jets of similar strength. This is reassuring that there is not a complete obstruction. The findings are compatible with physiologic hydronephrosis of pregnancy. Postpartum (not shown) the kidney returned to normal.