Chorionic villus sampling (CVS) is a test performed in some pregnant women to screen their babies for the diagnosis of any birth defects or pregnancy-related issues. Chorionic villus sampling can also help in early diagnosis of any chromosomal disorders e.g. Down’s syndrome or for any genetic problems e.g. cystic fibrosis or sickle cell anemia. In Chorionic villus sampling, a small part of the chorionic villi (a small sample of cells) is taken from the placenta and from there it is attached to the wall of the uterus for the diagnosis and testing. The sample to be used for testing can come from either the abdominal or the cervix wall. At the time of pregnancy, the placenta supplies nutrients and oxygen to the unborn baby and also cleans the baby’s blood by taking out the waste.
Chorionic villi are very small wispy protuberances that form the placenta. They develop from the fertilized eggs and share the genetic makeup of the baby. They have the genes which are very similar to the genes of the baby.