What is the primary cause of an ectopic ureter?

An ectopic ureter occurs when one or both ureters do not attach at their normal position on the bladder but instead open in an abnormal location. This condition originates from a developmental issue during fetal growth, where the ureteral openings are not formed or positioned correctly as the urinary tract develops. This abnormal positioning can lead to complications, including urinary incontinence or recurrent urinary tract infections, depending on where the ureter drains.

The other options pertain to different issues related to the urinary system. Acquired obstructions, such as those from kidney stones, typically cause blockage in a normally positioned ureter rather than changing its surgical anatomy. Infection in the urinary tract does not cause ectopic ureters, as this pertains primarily to the functional aspects of the urinary tract rather than its anatomical formation. Trauma may lead to various injuries to the urinary system but is not a cause of ectopic ureters, which are inherently congenital developmental abnormalities.