This site is targeted at medical and radiology professionals, contains user contributed content, and material that may be confusing to a lay audience. Use of this site implies acceptance of our Terms of Use.

Fetal megacystis

Fetal megacystis refers to the presence of an unusually large bladder in a fetus. It is generally defined as a 

  • bladder diameter > 7 mm in the first trimester 3
  • bladder diameter > 30 mm in the second trimester reference required
  • bladder diameter > 60 mm in the third trimester reference required

Epidemiology

The estimated incidence of antenatal imaging is at ~ 1 : 1500 pregnancies.

Pathology

It can result from a number of causes but with the main underlying mechanism being either a distal stenosis of reflux.

Associations

Associated anomalies are common 6 and include 

Radiographic assessment

Antenatal ultrasound

Will show an enlarged bladder

Ancilliary sonographic findings

Treatment and prognosis

The overall prognosis can be variable from progressive obstruction to spontaneous resolution. A follow-up ultrasound is necessary to correctly interpret the significance of megacystis detected in the first trimester

If the fetus is chromosmally normal and there is megacystis on the 1st trimester scan

  • there is spontaneous resolution of the megacystis in about 90% of cases when the 1st trimester longitudinal bladder diameter is between 7 - 15 mm 4.  
  • if the bladder diameter is > 15 mm there is a very high likelihood  of associated with progressive obstructive uropathy 4

Management will depend on the underlying pathology

Updating… Please wait.
Loadinganimation

 Details successfully updated.

Error Unable to process the form. Check for errors and try again.

 Thank you for updating your details.