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30 years
I am 13 weeks pregnant. in my echo dr found out my baby has a big bladder measuring 15.5mm. what are the chances to go all through the pregnancy and deliver a baby with normal kidneys?
Jul 14, 2013

Dr. Zakia Dimassi Pediatrics
Fetal megacystis (enlarged bladder in utero) 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
-bladder diameter > 30 mm in the second trimester
-bladder diameter > 60 mm in the third trimester.
It is estimated to occur in 1:1500 of antenatal imaging.

Associated anomalies are common and include:
-posterior urethral valves
-chromosomal anomalies:
on a first trimester scan ( 10 - 14 weeks), if the longitudinal bladder diameter of 7 - 15 mm there is a risk of a chromosomal defects is esimated at ~ 25%; if the bladder diameter is > 15 mm the risk of chromosomal defects is estimated at ~ 10%
-oligohydramnios
-megacystis microcolon intestinal hypoperistalsis (MMIH) syndrome (Berdon syndrome)
-megacystis megaureter syndrome
-prune belly syndrome

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. If the bladder diameter is > 15 mm there is a very high likelihood of associated with progressive obstructive uropathy.
Management will depend on the underlying pathology.
Due to limited characters here, I did not go through every pathology in detail- kindly discuss them with your physician and explore all your options for management.
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