I am 20 weeks pregnant and my ultrasound showed a choroid cyst on my baby's brain. The doctor said it might cause problems for the baby such as Down syndrome or mental retardation. I am supposed to have an amniocentesis next week to evaluate this further. Is the choroid cyst really that bad?
This is an important question because it comes up frequently and can be scary and confusing. A choroid plexus cyst is an ultrasound finding sometimes referred to as a "marker." In itself, the cyst doesn't cause a problem or represent a defect in the brain—usually it actually resolves by later in pregnancy. Although choroid plexus cysts are often found in typical fetuses, they occur more frequently in association with serious fetal conditions such as trisomy 18. Because choroid plexus cysts are seen more frequently in fetuses with trisomy 18, the finding shifts the odds that a fetus has this chromosomal condition.
Amniocentesis is a way of obtaining fetal chromosomes to test for trisomy 18 and several other genetic conditions. The procedure, in which a needle is placed through the mother's lower abdomen to draw out some amniotic fluid, has a small chance of causing a miscarriage. The purpose of amniocentesis is to check for chromosomal abnormalities, if the family wants this information at this point in time.
Not all families with an increased chance of chromosomal problems choose to have amniocentesis. I have had parents tell me that they wouldn't terminate the pregnancy and therefore didn't want to take that small chance of causing a miscarriage. Other parents choose amnio because they would terminate, or because they want to be more prepared before the baby is born. And keep in mind that amniocentesis may show that the fetus has a normal chromosome count and isn't expected to have any medical or developmental problems.
A genetic counselor can help you make these difficult decisions. Genetic counselors are not only trained in genetics, they are true counselors ready to help you make the decision that is right for you and your family. I highly recommend scheduling an appointment with a genetic counselor within the next few days, so you can take all factors into account as you choose your path.