Choroid Plexus Cysts seen during 20 week scan

  • What are Choroid Plexus Cysts?

The choroid plexus is a specific area of the brain, within which there are several glands which produce fluid to lubricate the brain. Sometimes these glands become blocked and the fluid collects producing areas which appear as choroid plexus 'cysts' under ultrasound examination.

  • What effect will the cysts have on the fetus?

Most commonly none. About 1-2% of normal pregnancies will show these cysts on ultrasound examination at 20 weeks and in the vast majority of cases, the glands become unblocked and the cysts just disappear naturally.

Sometimes the cysts do not disappear, this does not mean that there is a problem since many normal individuals also have choroid plexus cysts. The cysts themselves are not associated with mental retardation or brain abnormalities.

  • Will I need to have any further tests?

You may be offered a further scan later in the pregnancy just to see if the cysts have resolved.

In combination with other 'risk factors', choroid plexus cysts are (occasionally) associated with chromosomal abnormalities like Down's syndrome. Therefore, if there are any other suspicious features on the scan, or if you are older and therefore considering the option of invasive testing anyway, you may be offered an invasive test (cordocentesis or amniocentesis) to exclude the possibility of Down's syndrome or any other chromosomal abnormality.

Remember, If the cyst(s) are still present but the amount of liquid has not increased and there are no other markers of chromosomal abnormality on the scan, choroid plexus cysts are extremely unlikely to have any effect on the fetus.

Return to Home Page