Please respond doc, I'm very worried.

So far in my pregnancy I have had 2 ultrasounds. In both ultrasounds my doctor told me that my unborn girl has a unilateral choroid plexus cyst. She did explain that she is only telling me because she thoughton't know, but it is notheing to worry about because the size of the cyst is only .5cm. Now I know that she said it was nothing to worry about, but I am worried about it. She had blood work done on me (to test for any birth defects like down syndrome) and it came back normal. So she once again said it is nothing to worry about. The 1st ultrasound taken at 13 weeks and the 2nd ultrasound taken at 18 weeks and the size of the cyst is still the same. It was suppose to be gone by 26 or 28 weeks why isn't it getting smaller. She constintly says it's only on 1 side and very small not to worry but if I want to ease my mind I can have an amniocentisis if my next ultrasound sees the still cyst  (next ultrasound at 28 weeks, I am now 24 weeks). Should I be worried? and if the cyst is still present should I get the amniocentisis? or is the cyst to small to worry about? Thank you very much  for any help you can give and sorry for the long story, but as you can see I am worried. Thanks Again.

[Lisa Kessler, MS, CGC]

It can bring a great deal of anxiety when something unexpected comes up during a pregnancy.   As you may know, choroid plexus cysts are a common finding on level II ultrasound and can be associated with an increased risk for trismomy 18 and trisomy 21.  These are both disorders in which a pregnancy has an extra copy of a chromosome.  However, the majority of pregnancies with isolated choroid plexus cysts do not have chromosome problems such as trisomy 18 or 21.   You mentioned having an amniocentesis.  Amniocentesis provides definitive information about whether the pregnancy has any chromosome problems and has a risk of miscarriage from 1 in 200-1 in 500.  

Prenatal testing is complex and quite personal. Some women choose to have no testing during pregnancy because they are not interested in having information about birth defects until their baby is born. Women have many options and should think all of them through considering the medical facts and their own personal/family values.   You may benefit from discussing your options with a genetic counselor.  You can locate a genetic counselor through the NSGC website.  Best wishes to you.