Chorionic villus sampling (CVS) or chorionic villus biopsy is a prenatal test done to check chromosomal abnormalities of an unborn baby during pregnancy. CVS testing is taken if you are at risk of having a baby with some disorder. CVS is recommended by practitioners if you are age 35 and older, have a child with a similar abnormality, or if there is a family history of some genetic disorder in any of the parent’s family.

The testing involves taking a small sample of the cells from the mother’s placenta which forms during the pregnancy. The doctor takes a small sample from the placenta, a nourishment-providing organ that forms in the pregnant mother during pregnancy. The cells extracted for testing are chorionic villi or tiny forms of placental tissue and have similar genes to the mother. Apart from testing genetic disorders, CVS also confirms the sex of the unborn baby.
chorionic villus sampling test

Why Is CVS Done And What Does It Identify?

The mother can undergo CVS testing if she is 10 to 13 weeks pregnant. CVS testing diagnoses the following genetic diseases in an unborn baby:

Down Syndrome:

A genetic disorder caused by the abnormal division of cells that creates unrequired copies of chromosome 21. This can delay physical growth, cause intellectual disabilities, and alter the facial features of the baby.

Cystic Fibrosis:

An ailment that causes mucus build-up primarily in the lungs affecting normal breathing.

Tay-Sachs Disease:

This genetic problem causes fatty proteins to build up in the brain. It affects sight, hearing, and overall mental development. Quite fatal, children with Tay-Sachs do not survive after the age of 5.

Sickle Cell Disease:

Also known as sickle cell anaemia, it is a group of disorders of inherited red blood cells that affects haemoglobin. It causes infections, damage to organs and stroke in certain cases.


A rare inherited bleeding disorder due to which the blood does not clot since the body does not have enough blood-clotting proteins. 

Edward Syndrome:

Edwards syndrome, is caused by the presence of a third copy, sometimes a full and at times a partial one of chromosome 18. The fetus has slow growth and after birth the development of the body is poor.

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Who Needs CVS Test?

Doctors advise CVS test if you have abnormalities detected or certain risk factors during early ultrasounds. Otherwise, CVS testing is not a requisite during prenatal care. Taking the test can benefit the baby as it can detect genetic conditions during early pregnancy. However, it is upon the parent’s decision to completely refuse the test or take it.

What Are The Benefits Of Chorionic Villus Sampling Testing

Accurate Results

The results of CVS are usually obtained within 10 days and are quite accurate. Though they do not confirm the severity of the disorder, the identification of the abnormality is accurate.

Critical Information

CVS testing provides information which is not just critical but also important in terms of decision making that helps parents to make the best healthcare decisions. If the disease is critical and requires not going ahead to decide with the pregnancy, parents can decide on the termination based on the results. It can also help the parents to prepare for an emergency that may come along with the birth of the child.

Timely Decision

The testing also prepares the patient to make a timely decision as delaying it further can pose risk to both mother and child. CVS testing helps parents to make choices at the beginning of the pregnancy. The termination process is safer the sooner it is done.