Q: I am 20 weeks pregnant. I have undergone triple test and the reports are negative. I have also gone through the ultrasonography Obs level II, in which I got to know that the fetus is having bilateral choroid plexus cyst. I am very worried about it and I want to know why the cyst has developed? What may be the risk associated with it and what should I do?

A:You will need a repeat test to confirm the diagnosis and make sure there is no chromosomal condition like trisomy 18. In which case an abortion may be needed. If however, it is not so, then follow up scans will be done. Choroid Plexus Cysts The choroid plexus is the area of the brain that makes the spinal fluid that surrounds the brain and spinal cord. There are two of these areas in the brain, one on either side. This is not an area of the brain that is involved in thinking. Once in a while a cyst forms inside the choroid plexus and is called a “choroid plexus cyst” or a “CP cyst”. Cysts can be found on one side or on both sides and they come in many different sizes. A choroid plexus cyst does NOT cause learning problems or mental retardation and are not cancer. Although it can be scary to hear the two words “cyst” and “brain” in the same sentence, these cysts are not known to cause any problems for a baby. Choroid plexus cysts are seen in approximately 1% (1 in 100) of all second or third trimester ultrasounds. They usually disappear during the third trimester but they don’t always. It doesn’t make any difference if they disappear or not. These cysts can also be found in adult brains and go unnoticed during our lifetime. If mothers have other risk factors, a choroid plexus cyst may suggest that the baby has a higher chance of having a chromosome change such as Trisomy 18. In cases like this, more testing will be offered to you. Trisomy 18 is a very serious medical condition caused by an extra copy of chromosome #18. Most babies born with Trisomy 18 cannot survive long term.