Duplicated Collecting System (Also Duplicated Kidney)
In a normal urinary system, there is one ureter, the tube that drains urine from the kidney to the bladder. A fetus that is diagnosed with a duplicated collecting system (sometimes called duplicated — or duplex — kidney, or ureteral duplication) has two ureters for one kidney; each one drains separately into the bladder. This condition is often associated with a fetal ureterocele, a balloon-like malformation of the area where the ureter enters the bladder. This condition is most commonly found in females and generally affects 15% of all live births.