Hydronephrosis in a pregnant renal transplant patient.

Although pregnancy can cause hydronephrosis in native kidneys, renal transplant dysfunction during pregnancy due to obstruction is rare. A 22-week pregnant renal transplant patient presented with deteriorating renal function (serum creatinine 5.22 mg/dL from 2.07 mg/dL 3 weeks previously). Ultrasound showed transplant hydronephrosis with the graft compressed between the gravid uterus and liver. Percutaneous nephrostomy was placed with improvement in graft function. The nephrostomy remained in situ for the rest of the pregnancy. The nephrostomy was removed postpartum with no recurrence of hydronephrosis and subsequent transplant biopsy showed no evidence of rejection. The gravid uterus may obstruct a transplanted kidney.