While a puppy is still in the uterus, a hollow tube called urachus drains the urine from the bladder of the fetus to the allantoic fluid stored in one of the membranes that protects the fetus. At birth, when the umbilical cord ruptures, the urachus begins to degenerate; no urine should then pass through it. Detection of moisture or urine coming from the umbilical structure of a puppy indicates the the urachus is still open, or patent, and that the urine is passing through it from the bladder. Patent urachus, also called persistent urachus, increases the risk for bladder infections and urinary incontinence in young dogs. If umbilical swelling, skin discoloration and dermatitis develop soon after birth, vigorous therapy and amputation of the urachus are then necessary to avoid complications.