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Primary megaureter in infants and children

Laurence S Baskin, MD, FAAP
Section Editor
Duncan Wilcox, MD
Deputy Editor
Melanie S Kim, MD


Megaureter is defined as a ureter that exceeds the upper limits of normal size. In children, any ureter greater than 7 mm in diameter is considered a megaureter based on measurements in fetuses greater than 30 weeks gestation and children <12 years [1].

Primary megaureter is a result of a functional or anatomical abnormality involving the ureterovesical junction (figure 1), whereas secondary megaureter results from abnormalities that involve the bladder or urethra (eg, myelomeningocele/neurogenic bladder, and posterior urethral valves).

Primary megaureter in infants and children will be reviewed here.


Primary megaureter is classified according to the presence or absence of reflux and obstruction. Management of primary megaureter depends upon the type of megaureter. (See 'Postnatal management' below.)

The types of megaureter are as follows:

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Literature review current through: Nov 2017. | This topic last updated: Aug 17, 2017.
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