Infection and pain. Nephrostomy tubes are used to allow drainage of urine from the kidney if there is an obstruction preventing urine from draining through the ureters and bladder. The main risks of a nephrostomy tube are bleeding from the procedure, infection and pain where the tube sits. An alternative may be a ureteral stent. The pros & cons should be discussed with your OB and urologist.
Bleeding. Bleeding, ureter damage, infection, and puncture of unintended structure are complications of nephrostomy. That said, the procedure is safe and I have performed hundreds of them.