Ureteral stone in pregnancy leading to hydronephrosis and perinephric fluid from presumed ruptured calyx in patient at 14 weeks gestation

(A) Transabdominal longitudinal view of the right kidney shows severe hydronephrosis. Perinephric fluid (arrowheads) is seen from a presumed ruptured calyx, indicating obstruction.
(B) Transverse and sagittal transabdominal views of the bladder show 1 or 2 distal ureteral stones (calipers) with the ureter just above the ureterovesical junction and the distal ureter (arrowhead) dilated to that point.
14 weeks of gestation is early for physiologic hydronephrosis to occur. Assessing for a ureteral stone is important for all pregnant patients with hydronephrosis but is particularly important when the constellation of findings are not classic for hydronephrosis of pregnancy. In this case, the early gestational age of 14 weeks makes hydronephrosis of pregnancy much less likely.