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Dr. David
Dr. David, Physician Experienced in Urology
Category: Urology
Satisfied Customers: 48768
Experience:  Board Certified Physician with extensive experience in Urology
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Fetus distended bladder

Customer Question

What is the normal bladder size of a 39 week old fetus? A scan today showed that the bladder was distended with a bladder size of 5.6cm. The fetus is on the large side and there is excess amniotic fluid (19cm). What is the most likely cause of the bladder being distended and is it likely to cause further problems based on how big it is now?
Submitted: 4 years ago.
Category: Urology
Expert:  Doctor Natasha replied 4 years ago.

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Customer: replied 4 years ago.
Relist: Other.
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Expert:  Dr. David replied 4 years ago.
This is Dr. David

the average bladder size for gestational age of 27 to 39 weeks is 57.2 mm or 5.72cm in size.

so a 5.6cm bladder is normal size.

a large fetus and excessive amniotic fluid can be associated with downs syndrome

how old is the mother? has she had ob evaluation during pregnancy?

has she had amniotic fluid testing or blood testing to check for down's syndrome in the baby?
Customer: replied 4 years ago.

The mother is 29. We had ealry tests for dowsyndrome which came back with a low chance of downsyndrome.


She has not had a fluid test or blood test for DS, she only had a blood test (week long finger pricks 4 x per day) for diabetes which came back negative, although she did recently test positive for sugar in the urine.



Expert:  Dr. David replied 4 years ago.
actually 19cm of amniotic fluid is actually normal in amount.

why do you say tha this is excessive.

everything could be normal.

what is the baby's size on ultrasound?

39 weeks means she is due any week now.

she needs to get her blood sugar levels checked again for diabetes.

let me know if you have other questions.
Customer: replied 4 years ago.

Ok that's good news, we've been told several times that it's too much fluid and a high risk birth.


The main question was about the bladder size, so if you're sure 5.6cm is normal then thats great. The doctor told us is was distended and that a normal size bladder is 2.5cm, so if you're sure it's 57mm then thats good news.

Expert:  Dr. David replied 4 years ago.
I see

here is the article

actually I read the article incorrectly. the article is studying 61 cases of megacystitis or enlarged bladder in fetuses.

the average size for these fetuses who had megacystitis for gestational age of 27 to 39 weeks was 57.2 mm or 5.72cm in size.

so I gave you the wrong information above.

the bladder is enlarged. this looks like enlarged bladder or megacystitis
Customer: replied 4 years ago.

I saw that article when I googled the condition. I want to know why it is enlarged based on the other symtoms. It is not megacyststis as there is no blockage.